OBD2 Scanners: Do’s and Don’ts of Using OBD2 Scanners

OBD2 Scanners: Do’s and Don’ts of Using OBD2 Scanners

Cars have become nothing short of computers on four wheels. The on board diagnostics or simply OBD2, introduced in car models as from 1996, has made it a necessity for every car owner to learn about car diagnostic tools.

OBD2 scanners are one of the many diagnostic tools that you can use to know what’s troubling your vehicle. The OBD2 scanner is the standard software that has been mandated by PA for use for all vehicles with an on board diagnostic software. This scanner can monitor the ignition system and auto transmission in modern fuel injected automobiles.

How does the OBD2 Work?

The OBD2 in the simplest language is a kind of monitor sensor that is able to gather data from a car’s engine and also other systems. The monitor can send different commands to the fuel injectors and to the different systems in the vehicles to measure things like crankshaft and camshaft position, air and coolant temperature, engine rpm, road speed, and throttle opening among others.

The OBD2 is a sophisticated software with so many self-checks to monitor and regulate the functioning of your car and in so doing maintain its good health for the longest time possible. This scanner can even self-correct the vehicles ignition and fuel mixture at every crankshaft revolution.  You however need to have an OBD2 scanner to interpret the results from the monitor.

Background on the OBD2 Scanner and its application

Most people enjoy having an OBD2 scanner even when they have no idea of what it does or what to do when the scanner gives them an error. That’s why it’s common to find people panic stricken when there’s a malfunction in the car. It’s as if they always expect that with an OBD2 nothing should ever go wrong with the vehicle.

The first indication of a malfunction is an ignited “check engine light” on the dash. This light, in the OBD2 standard language, is also called a malfunction indicator light (MIL). When that light is on it means there is a certain sensor in the car that has sent an error message to the powertrain control module (PCM) which it can’t decode.

So the PCM is really the one that will illuminate the MIL to warn you that’s there’s something wrong with the vehicle, although even when this warning comes your vehicle will normally still be running well. In fact, the only other thing that might indicate some kind of trouble with your vehicle is maybe an increase in the fuel consumption and power loss.

The PCM will store a diagnostic “trouble code”. This is what technicians normally checked for using different scan tools to know exactly where the problem with the vehicle is.

The OBD2 scan tool was previously only available to professional technicians mainly due to it’s high price. Luckily, the prices became more affordable for ordinary car owners to be able to purchase them.

Today you can purchase an OBD2 scanner model for as cheap as $20 for an extremely basic scanner that will only show trouble codes, to about $4000 for an OBD2 scanner with full features, upgradable gadget with a computer interface and that accepts the use of multiple languages.

Using an OBD2 Scanner

Using an OBD-II scanner doesn’t require any wizardry, gifts or talents. The process is pretty simple, and while different models may give slightly varying instructions, the following is a general process that most models follow.

  1. Turn off your vehicle and plug the OBD2 scanner into the standard OBD II data link connector which can be located under the dashboard on the driver’s side, the left side of the staring wheel. The end of the cable will normally have a 16-pin plug that should give a perfect fit into the cars outlet.
  2. Turn on the ignition key or run the car, whichever is in the manual, and give time for the scanner to initialize. Some scanner models will need you to press a power button for them to begin the initialization process. Again, it’s important to have the OBD2 scanner manual for the specific scanner so you’re sure.
  3. When the scanner indicates that it’s ready, key in all the data that is required. This will mostly include the type, model and make of the engine, VIN and others. You can then initiate a ‘read’ or ‘scan’ of the vehicles diagnostic system. Again for initiating the scanning, some scanner models will have a button for that while there are others that will demand that you go through a series of manuals.
  4. Once the auto scanner completes the scanning process, it will give you a diagnostic trouble code or several codes. You can either write these down, transfer them to your laptop using a USB cable or Bluetooth if your scanner is Bluetooth compatible.
  5. You can then check these DTC codes in the manual to understand what your car is suffering from. Most manuals will only show the basic codes but if you need more enhanced codes you can check for these on the internet because there are vehicle models that will normally have a supplemental set of codes online.
  6. When you have finished recording the error codes, turn off the vehicles ignition and then carefully unplug the OBD2 scanner.

Be Careful When Using the OBD 2 Scanner for Diagnostics Reading

When connecting the OBD-II scanner cable to the data link connector, be extremely gentle. This is because the 16 pins in the plug are extremely delicate and you can easily bend the pins or crack the plastic around the plug if you push too hard.

Always turn the ignition on or have the car running according to the instructions in the manual. Failure to do this might corrupt the scanning software.

It’s also very important that you drive around with the manual for the specific scanner model that you’re using. Fortunately you don’t have to carry a manual copy as you can simply download a softcopy one from the internet and have it on your phone, or carry along the CD-ROM copy of the manual. Most scanners will normally come with both a CD and a paper copy of the manual.

Inspection and Maintenance Menu

Once you’ve reset the MIL, the scanner will give you another option for inspection and readiness. What happens normally is that the PMC will normally be checking your vehicle to ensure that the fault has been corrected once you begin to drive it. The time duration in which you need to drive your car for the PCM to record readiness is mostly dependent on specific vehicle models.

It’s important that once you have interpreted the codes given by the OBD2 scanner tool, you immediately correct the fault or have your car looked at by a mechanic who will be able to correct the fault.

You should then turn the OBD 2 scanner again for I/M readiness.  This is important because in the event that your car goes for an inspection at the DMV or an independent station, the technician will normally test for I/M readiness using their own scan tool.  You certainly won’t get a sticker if your car fails to pass the test.

View Data Menu

Authentic and quality OBD 2 scanners will normally also have another menu for “view data”. This one lets you into the actual numbers being read by the PCM.

You can view data on oxygen-sensor functionality, rpm and engine load, and air and water temperature, among other potential trouble areas for your vehicle.

With this information it’s easier to know the problem with the vehicle and to determine if it’s worth attempting to fix it on your own to save money or if you need professional input for a more permanent solution.

If you have a pro-grade OBD2 scanner model, you will also have a graphics function. This is normally what technicians use to check several parameters while the engine is on.

If you understand how to read the graphs you have more advantage as it will be easy for you to diagnose the problem without the help of a technician.

Is There A Difference Between “OBD2 Reader” and “OBD2 Scanner”?

Most people confuse a code reader with a scan tool. Code readers are mostly less expensive and are used for simpler functions than OBD2 scanners. They’re able to shut off the MIL light and to read basic codes, but will mostly not offer any greater value.

Code readers are more ideal for trouble codes that are of a more “generic” nature. They are however nor capable of reading enhance codes or OEM which are mostly specific to vehicles.  Generic codes are also known as P0 codes, while the enhance codes are called the P1 codes. Enhanced codes mostly change depending on the model year and should be regularly replaced or updated.

The reason why it’s important that you purchase the OBD2 scanning tool instead of a reader is because the scanner can read both codes. There are certain types of faults in vehicles that will set a P0 code and not a P1 code or vice versa. Unless you’re able to read both codes it can be difficult for you to make the right diagnosis for your vehicle.

Also, unlike code readers, scanners are capable of also displaying the readiness status of the car’s OBD2 system monitors. I/M readiness are self-checks that the OBD2 will run to ensure that the vehicle is operating efficiently and that the error code has been cleared.

There are monitors that run each time the car is started while there are those that will only run under certain conditions of operation.

For example the evaporative emissions system monitor (EVAP monitor) also known as the “loose gas cap monitor” will run after a refilling session.

This checks for vapor leaks and may turn on the MIL or “check engine light” when after refilling the cap is left off or not well tightened. This will set the error codes P0440, P0442 or P0445. Another example of a monitor that will run only occasionally is the catalyst monitor that checks the catalytic converter’s efficiency.

The Check engine light will normally be turned off when the monitor senses a drop in efficiency.

What’s the importance of knowing about the readiness status? The readiness status is mostly what is checked at the DMVs office to confirm that your vehicle is in emissions compliance.

This means that if no codes are set (translates to no trouble found) after all the monitors have been run, then your vehicle is running clean and will pass an OBDII plug-in emissions test or a tailpipe smog check.

With a code reader you can easily clear codes and turn off the “check engine” light, but you will however not be able to check for readiness and may fail to get a sticker in case your vehicle finds itself at the DMV’s office.

Ask for Help If You Don’t Understand a Code Given By an OBD2 Scanner

It’s important to have your boundaries set right when it comes to what you can do with your OBD2 scanner.

Most professional mechanics warn that the trouble codes, normally listed as P0 or P1, are not the actual diagnosis of the vehicle. Unless you’re able to decode the error, it’s important that you have your vehicle looked at by a professional.

The trouble code P0131 for example is a general sensor code. What most people will think of doing when they get this code is to install a new sensor with the hope that this will clear the error and turn off the MIL lights. The bad sensor could also trigger a P0301 misfire code.

Sometimes you could have misdiagnosed this trouble code and a new oxygen sensor together with a new sensor socket may not solve the problem. You will know that the problem was not comprehensively solved if after a small spike in the rotational speed of the crankshaft the MIL lights are turned on again.

Don’t attempt to give the same solution that has seemingly failed to an error code that keeps coming on. There are modern vehicle engines and onboard control systems that can only be easily understood by a professional who understands it.

So unless you have the right tools and training to solve a problem, it is wise to have your vehicle checked at the vehicle repair shop. The good thing is that since you will have already identified the problem using your OBD2 scanner, you will know the kind of service you want.

Most professional repair shops will actually give you a discount if you know exactly what needs to be fixed since this will save them a lot of time scanning the OBD2 and reading the codes.

Like a majority of vehicle owners, you will mostly only know how to flush out your car’s radiator or perform a simple oil change. Making an attempt at more complex tasks for example replacing a timing belt when you neither have the tools nor the know-how might just plunge you vehicle into more problems and have it grounded until a professional mechanic can work on it.

Purchase the right OBD2 Scanner

There are lots of OBD2 scanner models in the market. It’s important that you choose the ones with quality standards so that you can maximize their function. Also when shopping around for OBD2 scanners, it’s important that you check one that is compatible with your vehicles onboard diagnostics tool.

Investing in a quality OBD2 scanner is something that you should not debate on. This is because the scanner will save you so much money that it will quickly return back the money you invested in it and even give you profits.

In fact, with a quality OB2 scanner, sufficient knowledge in mechanics, and proper automotive tools, you will be able to save 70 percent plus of money that you would have used on vehicle checks and repair.

There will of course still be specific circumstances that will force you to seek the services of a professional mechanic, but since you will have control over your automobile, these incidences will be greatly reduced.

Tips for Purchasing an OBD2 Scanner

If you’ve made the decision of purchasing an OBD2 scanner then it’s just proper that you purchase an advanced gadget. Apart from the compatibility of the scanner to your vehicles on board diagnostics, the first thing you want to look at is the latest technology in the scanner.

An advanced OBD2 scanner will be very efficient in informing you about the several critical mechanics like service light system, conditioning control, airbag control, and transmission control among others.

Having this information will help you keep your car in good condition and avoid unnecessary calls to the repair shop.

Another factor to put under consideration when shopping around for an OBD2 scanner is how user-friendly the interface is.

A user friendly interface will make it easy for you to operate the device. It’s not really that the interface should be complicated.

A scanner with an interface that’s easy to understand but gives information to entail is actually more ideal.

OBD2 Scanners: Do’s and Don’ts of Using OBD2 Scanners
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90 Responses to OBD2 Scanners: Do’s and Don’ts of Using OBD2 Scanners

  1. Regarding obd2 scanners, bought one from eBay to diagnose Toyota fault codes and turn off check engine light. Vehicle model year is after the stated earliest model year supported 1996, so supports OBD2. The product description did not include Toyota corolla, however the obd2 scanner luckily showed Corolla in menu (strange!). And regarding turning off check engine light, there is no instruction in the paper manual or option on the menu. we were only able to find resetting all codes. Satisfied with my obd2 scanner.

  2. The VCDS Lite didn’t work, so tried t.o.a.d obd diagnostics scanner and worked excellent on Audi RS 5 2018. Other OBD2 scanners didn’t work.

  3. In summary, this obd2 scanner I’m using from Autel is working well for diagnosing the MIL on a 2013 Holden. Easy to connect and obtain the obd2 error code along with brief description of the situation. A little further help from web research showed how to repair the issue. For a obd2 scanner, this worked well and was simple to use. Not bad for a sub-$30 obd2 tool.

  4. OBD2 stands for On-Board Diagnostic. It’s the standardized system that allows external electronics to interface with a car’s computer system. Meaning can connect car to laptop with obd2 scanner. It has become more important as cars have become increasingly computerized, and software has become the key to fixing many problems and unlocking performance.

    OBD2 has existed in various forms long before anyone ever uttered the words “infotainment” or “connected car.” It came about primarily because of two factors: the need to regulate emissions, and the mass adoption of electronic fuel injection by automakers beginning in the 1980s.

    Unlike carburetors or previous mechanical fuel-injection systems, electronic fuel injection (EFI) requires computer control. Like its predecessors, EFI regulates fuel flow into the engine, but it does so using electronic signals rather than mechanical bits. That created the first major need to put computers in cars.

  5. Thanks. Reading this article, ended up getting Ancel obd2 scanner from Amazon. Product works great. Very simple and easy to use. Very simple to read and erase codes.

    It not only gives you the code it also tells you what the trouble is. I’m not a big instruction manual type, usually only refer to instructions when all else fails, that being said I used this scanner right out of the box without reading the instructions. It is self explanatory and easy to use. If you have a car that is 1996 or newer I highly recommend to others first looking around, consider how many obd scanner options there are on both eBay and Amazon. It is something I recommend you have in every vehicle and would even make a great gift.

    If you can’t fix the problem yourself you can at least know what the problem is when you take it to the car mechanic and you don’t have to worry about the Mechanic ripping you off by telling you there’s something else mulfunctioning with your car.

  6. Tried the Autocom Delphi obd2 scanner and it’s a great budget OBDII scan tool with bidirectional support. I also tried with my newer cars and a 98 Cadillac I wanted to get error codes and it worked great. If you need a simple scan tool that also reads other systems (besides engine/transmission), I then recommend researching for bidirectional scan tools. Those that are not, will only read simply generic OBD2, which are usually identified by their low price.

  7. Got a Bluetooth unit on Amazon. A powerful little device. It let’s you to scan codes, ABS faults, airbag faults, radio faults, body component faults, and likely some others I’m not recalling now. Not only doesn’t let you scan codes, it also gives you a description of the code and some probable causes for it. You could save these descriptions to dropbox, text them, or email them. It also allows you to clear the codes and view live data while the vehicle is Operating. You can see oxygen sensor real-time data, quantity of fuel in the tank, intake air temperature, coolant temperature, mass airflow sensor information, ambient temperature, control module voltage and much more. Depending on the obd2 scanners software, they are small but powerful scan tools. I wish they made a home based model that allowed by directional controls and some more in-depth monitoring.

  8. Just decided to purchase a OBD2 scanner from reading this and realized wish had bought one earlier! The small Autel obd2 unit works great and easy to use on my 2005 and 2008 vehicles. Based on auto parts store scans due to check engine light, I thought I had to do expensive fixing to pass emissions test. I easily cleared the codes with the obd2 scanner and the codes never came back and car passed emissions. The scanner also identified a legit code on another car so I would replace the part and avoid the check engine light. Instruction manual is concise. Identifies codes, clears codes, and shows when car is ready to pass emissions inspection.

  9. Excellent helpful article. Ended up getting the right obd2 scanner by advice contained here.

  10. Bought Launch X431. It works. Plug it in, and it works. Every time. Without fuss. Just works. Be happy, get code reader. Clears the codes, reads the codes, it’s all no problem at all. Don’t know about other tools here, but in my experience, any obd2 scanner is better then none.

    Considering mechanic charges $70 just to scan the car codes (not including fixing anything). This takes mechanic literally 30 seconds to whip in their OBD2 scanner into your cars port. Get an output. Print it out. And invoice you $70.

  11. Bought the ANCEL AD310. This is an excellent obd2 tool, with many more features than OBD2 scanners costing a lot more. Made it much easier to diagnose my emissions problem, and once fixed, I could safely reset codes.

    You can also see how many of the emission cycle tests are still pending in the onboard computer so you can wait until you have enough completed cycles to be able to pass.

    In many states, if you clear codes and then immediately go for emissions you will be rejected since the computer has not been able to run enough drive cycles, even though the CEL is not illuminated.

    • That is true in Wisconsin. My battery died in my vehicle and all codes cleared. I decided to reset the codes. After hundreds of miles of driving I could not get the IM readiness test to pass. My reader kept showing three monitors not ready. No check engine light, but could not pass the emissions test because my vehicle was rejected.

      • HOW DID YOU PASS THE READINESS TEST? I HAVE THE EXACT SAME PROBLEM. The dealership says I have to purchase a BRAND NEW OBD because they cannot flash/update the sys!! 3000.00 cost + labor

  12. Bought OBD 2 scanner from eBay. True lifesaver. Instantly showed whta problem was on car. Didn’t know anything about OBD before reading this site. So was curious and got one.

    • I’ve got a 2010 Corolla, myself. Before the Corolla, I owned 2000 Chevy Blazer, a 1999 Nissan Altima, and still have my 1999 Nissan Frontier. With every one of these, I’ve used, with a layman’s degree of success, an OBD2 scan device that I picked up a Craftsman OBD2+ABS, Model # 47156, at our local Sears store, when they were clearancing most of their tool items, in preparation of their store closing. Nevertheless, with a general knowledge of the workings of an internal-combustion engine, gears, hydraulics, and pneumatic, coupled with some years of industrial electro-mechanical experience, (not bragging, just showing that my little brain needs all pertinent info it can retain), I’ve not only been able to accurately, consistently, and easily troubleshoot component failure on all of the above-mentioned vehicles, but have also successfully diagnosed numerous friends’ autos, co-workers’, and even a couple of stranger’s vehicles.

      My point is, that with some mechanical aptitude, a general knowledge of how things go together and/or operate, a little bit of common sense (very little, in my case), you may only need a scanner for generic codes. On the other hand, however, if you have no mechanical (e.g. gears, diaphragms, etc.), electrical (batteries, relays, fuses, switches, loads, wire connections, electron flow, proper grounding, etc.), pneumatics (air hoses, vacuum hoses, breathers, etc.), or hydraulics (wheel brake circuits, fuel pumps, A/C circuits, etc.), then you may have a difficult time deciphering which code is for which system(s), and as stated in another ‘Reply’ on this page, if your vehicle isn’t under factory or dealer warranty any longer, and you don’t have a ‘Service Contractor’s or ‘Service Agreement’ with any other company, and you don’t owe a boatload on it, and you have a knack for DIY, it may be the perfect option for you. As with most decisions in life, haste makes waste, so consider what the experts on this page have shared with us, and if what I say lines up with them, then perhaps you can accept it as “okay” knowledge, (I reckon). Best of luck in your DIY endeavors!

  13. Never preferred an obd2 scanner on a laptop, but decided to give it a try. Got TOAD and ELM327 usb. This tool is fantastic! I used it on my car to determine the error codes for the check engine light, and was able to turn the check engine light off with this tool once I knew what was wrong. It was bigger than I expected it to be, being about the size of a computer mouse. I would highly recommend having this as an investment, and knowing yourself what’s wrong with the car; instead of some auto place maybe reading it wrong or making you buy the wrong part.

  14. Without obd2 scanner it’s hard to diagnose issues. That’s why auto technicians/workshops use them first before even manual checking. I highly recommend car enthusiasts to own a obd2 scanner.

  15. Decided on TOAD OBD2 scanner. It’s my second code scanner after “Autel MaxiLink ML619 CAN OBD2 Scanner Code Reader +ABS/SRS Diagnostic Scan Tool” from Amazon. It reads OBDII, including CAN format. I’ve only used it once to date, but it told me everything I needed to know and more. The manual that comes with it is very informative, describing not only the codes themselves, but pending codes and monitors. The software and ELM327 device will tell you about all those things, so not only will you know which codes have popped, but which might pop soon. Far more features that the more common orange-colored brand for the price. Highly recommended.

  16. OBD2 scanner Coding hasn’t been this easy! Plug to your OBDII port, choose one of our obd programming applications and start coding. By the way, the toad-pro software isn’t free but at $97, you can’t beat it. If you want all of the neat features that the BMW has hidden you’ll pay hundreds of dollars from BMW for them to code it for you. I purchased the Bluetooth version and it has worked every time!

    • ive got the same BMW and ive got a FOXWELL reader some how i got it to cut my headlights off and no idea how to get them back on?

  17. Long story, short version…I have a 2007 Camaro that was due for California reg and smog in June. I went to get it smogged, via obd2 scanner at mechanic, and it failed.

    Guy said drive, drive, drive. Okay. Put some miles on it brought it back and it failed again. I paid the reg fee already just needed the smog to pass.

    Talked to different smog places (they scanned again via obd2), drive drive that’s all I kept hearing because my battery had died before the test it wiped out the drive cycle memory. Looked on YouTube and saw a several about using this obd 2 scanner.

    Took the car out again today and had this plugged in the whole time. Finally after putting over 250 miles on my car the problem light showed the ok signal. Back to the smog shop and showed the tech to check via obd2. He thought this was pretty cool. Smog done! California sucks when it comes to this stuff so now I really polluted the air.

    Hence I recommend obd2/obdii scanner for anyone looking for peace if car will fail or not.

    • Yes never unplug or replace the battery before smog time because it will fail. Been there and done that too. Each manufacturer has a drive routine that must be accomplished in order for all the systems to be ready for smog check. 250 miles was a lot of driving on your part to accomplish this. Once I learned my cars driving needs, I was able to do them in about 30 minutes and drive right back to ththe smog place and have it pass.

      • What if your battery actually needs replacement before a smog test? Would the obd2 scanner rectify potential smog test failure with a simple reset?

        • INstall a computer power supply in the cigarette lighter or jump the batt terminals to keep power to the computer. Most auto parts stores have these especially in CA. BMW/Mercedes batt replacement REQUIRES keeping power to the computer or it’s programming is erased, in 2017 it was a $400 shop charge to reprogram. Basically a DIY preventative on their part.

          Owners manuals will warn about these items – but Americans never read them. It’s 8th grade level explanation, and yet most of my customers were overwhelmed.

  18. So want to read your engine fault codes on your own? Most modern cars (actually since 1996 in USA) have Engine Control Unit (ECU) computers that monitor engine components, and you can connect to the computer through a standardized port called an OBD-II (OBD2) port.

    First determine if your car has an ODB2 port, get an OBD2 scanner, connect to your vehicle and you can read any fault codes to find out what the ECU is reporting. You can easily perform a search on Google of those codes with your car make/mode/year and find out more information about what other’s may have reported as the likely fix for the problem.

    EG: Type in: P02342, and you’ll get tons of forums discussing the error and it’s solutions. Can find on Amazon. Just search for “obd2 scanner”.

  19. Saw the obd2 scanner review page and decide on “OBD2 Scanner Code Reader Car Diagnostic Tool – OBD 2 Check Engine Light Scan Auto Computer Readers with Reset ” from Amazon. It is Inexpensive and also clears codes and it reads codes. Codes also when showing up give an explanation of their condition/seriousness/caution. IE. Code P0441 shows up and under it reads something like EVAP Emmisions Control. Which generally refers to you in the direction of the Gas Cap or Evap Canister on the fuel tank. Or it may read P0421 Catalyst System Efficiency Below Threshold, letting you know you need a Catalytic Converter or an 02 sensor.

  20. Having trouble connecting to ELM327 was told to try connecting with the Engine running is this ok or can it damage the ECU

    • Yes, totally fine. It’s impossible for ELM327 to do any damage to ECU/car. Haven’t seen a single case like that in 10 years. ELM327 is not a tuner (changes ECU data). It’s only a reader. Hence ECU is totally unaffected by it’s use.

  21. Used Autel obd2 scanner as result of reading this article. It’s an dvanced diagnostic scan tool with one-click I/M readiness key, which is convenient to determine the vehicle’s condition. I also found that despite obd2 scanners claiming to support all cars, it’s usually not the case. FAct is, few models support manufacturer obd2 codes. Rest are generic obd ii pids. However the obd ii software by TOAD-pro supports lots of obd2 fault code pid’s.

  22. The Launch obd2 scanner’s I found excellent diagnostic scanner tools for use on variety of cars with multiple OEM manufacturer systems supported. But don’t expect the manufacturer systems working on all cars. That’s unrealistic.

    EG: I attempted to seek out a problem on a 2003 Ford’s ABS and got nothing. The light was on but no report about codes for the ABS system or the traction control. It did find an DTCs and shows Reported fixes. I was really hoping it would find the ABS.

  23. I have a Nissan Frontier 2004 model diesel motor and I am having a issue with the VP44 pump and I need clarity to fix it. I am a certify mechanic but these pumps have to be program to work with the ECU can this OBD2 reader/scanner help me to swap the software to put it on a virgin VP44 module…

  24. The obd2 scanner I’ve used (bought on eBay; SnapOn), works on Mercedes in the US, (E320 CDI) had a fault code for a glow plug situation. Read the error via the obd2 scanner and gave the correct PO code… unlike some of the cheaper obd2’s which couldn’t read car’s obd2 OEM fault.

    Honestly it works and it comes with lifetime updates. The lifetime updates are what really make or break these obd2 based scanners that and working on foreign vehicles.

    It does everything my older $500 obd2 scanner from x431 performs, speed is on par with any newer OBD2 tool. It’s not fast not slow just works in all no complaints. I plan to just leave it in my glove box or trunk and use as needed.

  25. I’ve been a professional in the automotive business for 22 years and have ASE L1 advanced diagnostic specialist certification. I can say that ELM327 was in general the best bang for the buck OBD2 generic device I have ever seen. Naturally it won’t do a lot of things that the more expensive equipment I use ($15k+) can do, but for quick checks and watching limited lists of live data it’s very useful. I use the Dashcommand app for Android, and this works extremely well with it – quick live data refresh rate, and good access to codes and freeze frame data. With other apps, I use it to monitor fuel economy in real time in my own vehicle. Nice job, BAFX. I wish everything worked this well for the money.

    • I’m also using a BAFX scanner on my Suzuki. Very useful and straightforward. It goes with a Torque Pro(Android) scanner App.

  26. My obd2 scanner, MultiDiag, is one I I think every car owner should have. It has an easy to use windows software and gives you the info you need on your car. Not only generic, but literally scans all OBD2 oem systems. Takes about 10 minutes in total.

    I like how it is simple for someone like me (not a mechanic, but ordinary car owner) to understand obd2 from scratch, when it’s layed out so well.

    There is no manual, but you get step by step install instructions and how to connect the main OBD2 scanner unit. Which is very helpful because it removes that moment of “what do I do first???”.

    I think this is a good obd2 scanner for anyone to use who is planning on buying a car from a seller. You can quickly see info about a vehicle that the owner may no know (or may not want to tell you).

  27. Stumbled on this and saved me lot of time and researching finding the right obd2 scanner for our European-Cars workshop. Another top for local mechanics is to attend an auto exhibition show, and see what’s on offer by other companies. Will give you good perspective on markets common obd2 scanners used by competitors.

  28. Somethimes i plug the scanner and the ignition is on but the scanner say the ignition is off and i try again but this time i start engine is start what is the problem !

  29. So I have a low pressure light on my 2014 Subaru Legacy. My dad gave me his OBD II diagnostic scanner to get it off. I plugged it in with the ignition on and tried to scan but nothing happened so I unplugged it with ignition still on. I did click ‘erase’ before unplugging to see if it would take the light off but it just said ‘erase fail’. When I tried to turn the car on it would start and then die. Wouldn’t stay on unless I revved the engine after starting. And even then the idling RPMs were lower than normal. Did I do something wrong? I figured because it’s just a scanner it wouldn’t effect the system. Any information would be great. Thank you.

    • This would either need oscilloscope or car mechanic to figure out. I can’t diagnose from here; too many variables involved.

    • I had the same thing happen after trying to erase code. The car will start and just die now. What did you end up figuring out was the problem?

  30. Tried one of car diagnostics plugs and get what you pay for when it comes to a obd2 scanner.

    The car diagnostics tool tool does very basic functions well, such as reading diagnostic trouble codes and checking for emissions readiness. Outside of these functions, I was unimpressed with the systems over all performance. It takes longer then you would expect to enter into the ECU. However outside of this for someone just looking for an affordable obd auto doctor for basic diagnostic ability on their car, this obd system was decent.

    Just don’t leave it in your vehicle, the glue used to attach the button labels to the front comes off if the adhesive gets too warm.

    • Same here. I bought one of obd2 scanners for 2 BMWs and I can say that it does many functions that I couldn’t do without it… like check engine light codes and such.

      I was able to read codes, and reset them, from many of the components on the car, not just the engine.

      Of course, this isn’t a dealer-level tool, so there will be things it cannot do, but I can tell you that as a BMW owner, it’s good to have this device nearby.

      One point I don’t like is that the page where you purchase the tool, it says that you get free lifetime upgrades on the software, and now I found out that it’s only 15 months of free upgrades. That’s disappointing. It has paid for itself already, so I’ll leave it at that.

  31. I’ve searched for proper obd2 scanner for last 3 months after having tried many. Problem is they all have positive reviews. So it’s hard to tell which is best. I consulted mechanic. And he recommended me tech-ii on ebay. It’s a obd2 tool that’s been around the block for decade.

    Purpose of this review is to notify readers to do your research. Just typing “obd2 review” isn’t good enough. Because there’s more to obd2 scanner, like: Can it reset service/oil indicator (99% can’t), can it do DPF regen (99% can’t). Do your own research please!

  32. One of the obd2 tools showed me the code, which I was then able to search online, and quickly fix the problem.

    Even if I take it to local garage mechanic, going into it with codes means I have some knowledge of the problem and the potential expense involved.

    So my conclusion of using obd2 tool is: Proactive troubleshooting can save considerable money in long term.

    • They showed you the fault code sure. And you have resetted it, definitely. But has the mechanical issue actually been replaced, or component fixed? Nope! Best one will get from obd2 scanners is “false peace of mind”, unless willing to but part on eBay or shop and fix the problem themselves in the car.

  33. l am looking into obd2 diagnostic tools an there are so many so it is confusing. Read most obd2 scanners do not support GM or Dodge ? I may have read things wrong but not sure thats why I am asking. I was looking at scan tools but thought doing pc obd2 package would be cheaper and have more benefits also to do different tests with. If any windows based obd2 program supports, I would like to know what all i need to order to do so . I would like to talk over the phone as there a lot more information that can be translated useful. Thank You for your time

  34. I used a obd2 scanner to get my 13 Mercedes-Benz SL500 to pass inspection. I failed my 1st inspection 3 weeks ago. So I bought this to know when the car’s monitors are ready. So yesterday I went to do a drive cycle, I drove 43 miles, highway, then stop & go traffic.

    When I returned home I performed scan on the monitors, the all had a OK next to them. So today I went to my car mechanic and passed inspection. Every car owner should own a obd2 scanner, to see what’s going on with your car. It helped me A LOT!

  35. Just received USB connector and Bluetooth for my new DIAGNOSTIC TOOL. I think it is an amazing tool! I will be fiddling with it……lots to learn!

  36. I’m considering buying an alternative odb ii code reader. We recieved an
    obd scanner bluetooth scanner in the mail and downloaded the software.

    I’m not seeing my IPR (injector pressure regulator) or ICP (injector control pressure sensor) PIDs in the list of PIDs that I can monitor. Without those this does me no good in diagnosing the no start issue with my 2004 Ford F350 6.0L diesel.

    I would also like for it to be able to run a cylinder balance once I do get it running along with cycling the injectors on at a time to test the injectors. Any car code scanner which could help with reading check engine light on Ford…

  37. I have a Hyundai Accent with the 1.6 Gamma MPI engine with ETC. The throttle body is the Bosch alloy jacket water heated type. The engine is in excellent mechanical condition and has no current or pending DTC’s.
     The engine idle has a consisted roll with about a 30+- RPM change. I don’t believe that it is happening in the open loop mode but is difficult to see. The roll occurs at idle either in neutral or drive. It is aslo difficult to tell if it is doing this under part throttle openings when in motion.
    Hyundai are not interested and have suggested a “thorough tune up” The unit is serviced @ 5K intervals and there have never been any issues. It has new plugs at last service and this did not change the RPM issue. Apart from the unstable RPM the vehicle functions OK. Battery voltage is at spec with new battery fitted. As it does not appear to manifest itself in open loop mode could it be an unstable pre cat O2 sensor??

  38. Hi. My car is a chevrolet van g2500 truck 6.5L diesel whit 4l80e a/t and I have problem whit the toad system. I logg in to my pcm in the car.

    But cant se any faultcodes and i cant se my automatic transmission in the program. I have a lot of fault codes, but Toad cant find them.

    I have 4wires obd2

    1 wire for class2
    2wires for ground
    1 wire for 12v battery.

    Which obd2 scanner or can obd-II reader help solve this, I wonder.

  39. I have a gearbox oil change coming up and there is a fluid injected into the exhaust system on my peugeot 3008 and I need to reset counters to turn the warning signs off. Wondering if obd2 scanner can fix this.

  40. Thank you for the info .i need to clear the key cods .i put a new ignition switch in my 2005 ford f 150 code p1601 can i clear the obd with my bosch enhanced obd 1& 11 scan toll

  41. Any obd2 scanner here which has ability to provide monitoring for specific signals, such as, REDUCT_TNK_P and REDUCT_INJ_DC#? And NoX sensors/module?

    Also, will it provide specifics in understanding cylinder misfires? Or is oscilloscope better then obd2 tool…

  42. hi there!!! i have owned an xtool x300p scanner but it failed to communicate with Honda Cr-v gen 2, Toyota commuter van 2016,Mitsubishi montero… that 3 car’s I’ve already try yet to scan i don’t know if it works on another car… any comment regarding this…

  43. My obd2 scanner gets the job done. It does what it is supposed to do and works actually quite well to my surprise. I just have a problem while reading some data instead of using some words it uses signs (shown in one of the pictures) to address to some data which annoys me a little because it confuses me. Other than that I’m very happy with ANCEL AD410. It saves you a trip to a mechanic and some money too. Updating it through the internet is very straight forward. Just don’t tell your neighbors you have one or they’ll start calling you each time they have an issue.

  44. Add some info about obd2 scanners:

    As a result of increasing emission levels around the world, many countries have enacted strict emission related regulations that will drive increased technology into the modern automobile in order to reduce the exhaust emissions. European and North American countries lead the way by adopting technology that will standardize the way these vehicles can be checked for compliance.

    The OBD-I (On-Board Diagnostics I) system was introduced in the early 1980s and by 1988 all new cars and light trucks sold in California had to have OBD-I.

    The fundamental elements of the OBD-I are the electrical components (which influence exhaust emissions) that are monitored by the engine management system. An optical warning signal is given in the event of an OBD-I relevant failure. This fault can be read out by way of a flashing code.

    OBD-II has been compulsory on all vehicles in the US market since January 1996. EOBD (European On-Board Diagnostics) is the European equivalent to OBD-II.

    It was introduced in 2000 and became effective in January 2001. There are a few differences between EOBD and OBD-II but none that will affect the generic scan tool operation.

    All the communication protocols for both programs are identical. Vehicle emission strategies and certification procedures vary between countries, states and regions. Always use the vehicle factory service information specific to the country and emission certification.

    EURO-3 is a continuation of the emission regulations known as EURO-1 and EURO-2. In addition to introducing stricter emission limits, the directive now also covers the monitoring of emission related components and functions during operation, i.e. EOBD.

    The OBD-II and EOBD system must show the failure of an emission related component or system to the driver using a MIL.

    What does OBD-II and EOBD mean for the Repair Shop?

    A universal or Generic OBD-II/EOBD scan tool can now be used on any OBD-II 1996 and newer and EOBD 2001 and newer vehicle, giving the shop more diagnostic coverage that was not previously possible.

  45. I would like to leave the OBD2 scanner hooked up to my car while driving, to monitor the “INC” of the emission scanning. Is that bad for the scanner? Is this bad for the car electronic?

    Thks for your answer

  46. I was wondering how to properly use obd2 scanner? Also can a obd2 scanner be utilized while driving; is it safe? And what obd2 vehicles are supported?

    Many obd2 scanners on the market, but unsure which to go for.

  47. A good shop is not going to give you a discount because you tell them that you already know the problem and you give them that information. Your bill maybe cheaper but that’s because it saved them time in diagnose the problem. They are still going to plug in their scanner and what not plus they are one doing the work and also I have been working on cars for over half of my life. I can count the times on one hand that the customer has been correct at figuring out what the problem is. Sure I take all the info the customer tells me into consideration but that’s it. I will still find the problem on my own and fix the problem. I love it when a customer thinks they know the problem.l but just can’t seem to fix it. So they tell me and I end up fixing something else and they get made at me because I didn’t listen to them yet after they are done crying they realize I FIXEd the problem. The scanners are just another tool that helps when diagnosing a car. They are not perfect and they don’t always give you the correct info. It’s still important to have a good trustworthy mechanic and not to think the customer knows more then someone who works on cars for a living.

  48. Thanks, we find this article on outlining how to use a obd2 scanner useful in our decision to renew workshop with newest (either Launch/autel) car code scanners.

    For the rest of us, how to use a code reader? Just matter of plugging into port under steering wheel. Don’t worry, it can’t damage car, as it’s reading obd sensors only. It can’t change data.

    So far, we’ve stuck with Snapon car code scanner, but recent development has made ob2 reader far affordable for fleet like ours.

  49. I bought a Kyzee 501 from Ebay, they sent me a Kyzee 301 I asked for a refund which they did and said keep the 301. As it happened the 301 was all I needed. I have a vauxhall vivaro, seriously, never buy one they are an absolute nightmare of errors, I mainly suffer from P2263 and P0409 so turbo pressure sensor and egr sensor I think also had a MAF error always going into limp mode.

    Just saving up to get a different van like a Peugeot Boxer or a Merc Sprinter if I can find a clean one.

  50. I bmneed a data transfer cable for advantage pro eetm303 to go to obd2 can sombody please help me?

  51. Been search for how to use a obd2 scanner or code reader for our Land Rover supporting “can obd2”. My only skepticism is what if get one can obd2 scan tool…. and miss out the features on others.

    Do they basically all scan the same? Or we should be asking a different? I already know how to use a obd2 scanner as it’s matter hooking up and turning on car ignition.

  52. In the comments I’ve seen several people asking “Can I drive vehicle with scanner/reader connected without damaging either the scanner or vehicle electronics?”, My guess is that in some situations, there could be some damage but that would be the more expensive scanners. If this is the case, would the lower end scanners be safe to be connected while driving? What functionality in a scanner would make it a bad idea to drive connected?

    Also,the scanner I just purchased (Autel AL519) warns, in User’s Manual,
    to “plug-in and unplug” ONLY with engine not running and IGNITION OFF.

    OK, before posting I just found the answer to my question in the User’s Manua
    that for my scanner:

    It is acceptable to drive with the equipment connected. It mentioned driving in
    “Ready Test Mode” to continue driving whle while the different “Readiness
    Monitors (IM Monitors) become ready for smog test”

    I reckon I was too much in a hurry to play with my new little toy before doing what the manufacturer suggested ..should have read the entire Manual, would have taken maybe an additionsl 20 minutes. Hopefully somenone will benifit from my laziness

  53. OBD scanner might point you in a general direction of the code error-You need to be very knowledgeable about the vehicles sensors plus the wiring and electronics of said vehicle to solve the problem. Can you look under the hood and trace every wire? Do you know how to use a DVM and low Volt test equipment? Can you read an Oscilloscope pattern. Trust a certified shop tech and save yourself from frustration.

  54. Summary on how to use obd2 scanner:

    1. Ensure power of car is turned off and the code reader is plugged into the OBD2’s port. It’s under stearing wheel, and even further down (where legs are).
    After plug the scanner into yvehicle’s port, the can obd2 scan tool will start working.

    2) Turn on car power and wait for obd2 scanner to boot up (or show on Windows if it’s Bluetooth).

    3) When the code reader is ready, input all of the required data: information about car’s Vehicle Information Number (VIN), engine, type, model, etc.

    4) Allow the obd2 scanner to read the data of the car.

    5) Enjoy the results. Don’t be suprised if doesn’t show anything, as it usually means you’ll need a more expensive OEM code reader (which can also scan ABS, electronics, EGR, electronics)… which generic obd2 scan tools can’t do.

    And that’s folks, how to use obd2 scanner, code reader or whatever it’s called. 🙂

  55. Hi Sir/ Madam
    Mailing to Inquire if you have in stock Automotive Code readers and scan tools, Kindly send me a quote for 20 pieces and the Grand total with tax and also let me know if you accept Credit Card transactions.

    Thank you

  56. I have a ELM 327 OBD II scanner in which when i try to scan DTC it doesn’t show any trouble even MIL, airbag and Sedimenter light is on in my instrument cluster i am not able to identify what is the problem can anyone help?

    • The sedimenter light mostly turns ON while you have bad fuel mostly with water content or impurities within the fuel system I think.
      It’s better to check with your auto mechanic as you have the MIL and airbag one also lit up. These ones are really something not best to be handled by end users.
      * Especially the MIL fault is not supposed to be ignored.
      * When the Airbag light is on, the airbags might not work in the event of an accident.

  57. To use an obd2 scanner, should first know 1 thing: 95% can only scan Engine data. The rest 5% are more expensive and can also scan ABS, Airbag. Be cautious of this fact when buying. As often people rush into obd2 scanner, only to realize it doesn’t return much useful data.

  58. When you want to purchase a new scanner for your car, you will need one with OBD2 compatibility. OBD2 ports are usually found under the steering column. The BlueDriver system plugs into the OBD2 port on your car and communicates with a Bluetooth app on your smartphone. You can see live data reports and perform a smog test on your car while using it. BlueDriver also recommends possible repairs for specific codes. While this system is simple to use, it does not come with a lot of accessories. You will also need a smartphone to use it.

  59. The OBD2 Scanner is the simplest and most convenient way to monitor your car’s electronic components. It is an integral part of today’s cars and can help you monitor engine, ABS and battery data. It can be connected manually or wirelessly.

  60. Is this statement correct: “The Check engine light will normally be turned off when the monitor senses a drop in efficiency.”

    I thought the MIL would come on for that condition.

  61. Someone was asking here, “what does i/m mean on a code reader”. So thought I help out…

    I/M stands for Inspection and Maintenance. On a code reader or scan tool, I/M refers to I/M Readiness, a function that checks if your vehicle’s emission-related systems are ready for inspection and maintenance testing. The purpose of I/M Readiness is to ensure that your vehicle is meeting emission standards and running efficiently.

    An I/M Readiness test checks various emission-related systems, such as the oxygen sensor, catalytic converter, evaporative emissions system, and more. These systems are monitored by the vehicle’s on-board diagnostics (OBD) system, which records information about their performance. If the OBD system detects any issues, it will store a Diagnostic Trouble Code (DTC) and may illuminate the Check Engine Light on your dashboard.

    When you use a code reader or scan tool to perform an I/M Readiness test, the tool will indicate the status of each monitored system:

    1) Ready or Complete: The system has been checked, and no issues were found.

    2) Not Ready or Incomplete: The system has not yet been checked, or the vehicle has not been driven long enough after a previous repair or reset for the OBD system to gather sufficient data.

    3) Not Supported: The vehicle’s OBD system does not monitor this particular system.

    Before a vehicle can pass an emission test, all of its applicable I/M readiness monitors must be in the “Ready” or “Complete” state. If any are “Not Ready” or “Incomplete,” you may need to drive the vehicle for a specific drive cycle or fix any existing issues before it can pass the emission test.

  62. This article outlines the dos and don’ts of using an OBD2 scanner, including how to connect and use an scanner to read codes, clear codes, and check monitors. Purchasing a quality scanner and knowing your vehicle’s diagnostics are key to troubleshooting check engine lights yourself.

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