ELM327 Interface Reviewed – What You Need to Know

ELM327 Interface Reviewed – What You Need to Know

Since the introduction of On Board Diagnostics from 1996 onwards – it has become increasingly difficult for mechanics and do-it-yourself’ers to service and effectively perform repair work on vehicles. It was usually done with non-standardized tools. Meaning what works for Mercedes, doesn’t work on GM’s for example.

However, as ELM327 chip got improved (which is capable of reading standardized OBD system) – it’s now making it possible for mechanics or car owners, anywhere in the world, to accurately diagnose car faults. Unlike years ago when even trained personnel struggled with keeping up to date with different protocols that each car manufacturer designed.

Hence the OBD-II system that was introduced and was used by all the car makers worldwide, has made it a lot easier, but still required expensive and multiple tools to scan and read the diagnostic codes.happy-car

Simpler devices were developed but they could generally not diagnose driveability issues across the whole vehicle, but only specific functions (like just resetting oil/service interval).

So when ELM327 came along, it’s microcontroller finally provided a UNIVERSAL solution to diagnosing vehicles fitted with OBD-II systems.

Of course, it’s as good as the expensive professional scanners (like $5,000+ SnapOn) – but it has made it affordable and provides the information that most mechanics require to service or repair their cars.

How to Use ELM327 Interface (BT, WIFI, USB Cable)

ELM327 scanning devices cannot be used as a standalone device and hence the cheaper prices.

They are used with what most people already own… such as smartphones, tablets and MAC/Windows laptops.

Meaning the user is required to download the app either for Android, iPhone, Windows or Mac… and only then will the interface communicate or login into cars OBD system via WiFi, Bluetooth or USB interface.


The ELM327 OBD-II interface is compatible with Window, Linux, OSX, Android, iPad and iPhone.

It can be connected to all your devices by using Bluetooth, USB or WiFi except some devices are not compatible with the different connecting methods.

The Windows, Linux and MacOSX will connect using all three methods but with Android, it will only connect using Bluetooth and iOS will only connect using WiFi.

The diagnostics that you are able to do with the ELM327 are listed below:

  • Check and clear the check engine light and with its real-time data sensors, you are able to check all the engines functions such as horsepower, the revs, acceleration, throttle, speed, boost and coolant temperature.
  • You are able to log this data onto you Smartphone or your laptop
  • Record all the lap times, acceleration, speed and view the results on your laptop or Smartphone which can be displayed in graphs.
  • It can provide diagnostics such as fuel consumption, the oxygen sensor ratios, the boost and coolant temperature.

It is important to note that iOS system will not work with Bluetooth scanners and that is because of the way Apple Bluetooth systems are configured therefore if you have an apple device it will be better to use a scanner that has a USB or WiFi connection.


Software/Applications Used By ELM327 Interface

There are several software packages that can be downloaded and lots of them are for free. Like all software, they offer different features from very basic to quite detailed programs.

Generally, if you want a high powered analytical program then you will probably need to pay for software. There are basic programs that will be sufficient for most do it yourself mechanics out there.

How to use the ELM327

Once the software has been downloaded then the interface and the computer or mobile device need to be paired. The interface is plugged into the relevant plug of the car and if you are using a USB connection then plug the USB into the computer.

The Bluetooth connection is paired in the normal way as any other Bluetooth device and with the wireless connections the wireless settings are defined in the normal way and will probably require a passcode.

Once the two devices are connected then switch on the vehicle ignition. The dashboard lights should be lit and then press the connect button.

The software will automatically connect the vehicle between the two devices. There will be a LED light on the interface device which will show if the computer or mobile device are connected.

Once that is done you can start doing the diagnostics and repair whatever needs to be repaired.

Is ‘this’ EM327, the right Interface? (Dealing with multiple brands)

That all depends on why you need the diagnostics. Is it for various vehicles or are you just a weekend mechanic that services your own vehicle.

With the EM372 interface, you require installing the software that is appropriate for the device that is being planned to be used for that purpose whether it be a laptop or mobile device.

It is also worthwhile to do some research because some of the software works better with different models of vehicles.

The advantages of having software that is developed for Android or other mobile devices is that there are plenty of add-ons that can be downloaded and can successfully be used to diagnose the fuel consumption and other functions of the car to get better fuel economy.

These type of functions are easy to read on the computer or mobile device and are well within the ELM372 capabilities.

Even though the ELM327 scanner is classed as a basic code reader with limited capabilities it is able to show the mechanic which codes are faulty and clear them.

There are some basic parameter IDs but with this technology, there is software being developed that will allow you to do more comprehensive diagnostics, extract performance statistics and basically be able to see all the functions of the engine and how they are performing.

With the more advanced software available you can also diagnose engine data and parameters that some handheld scanners will not be able to do.

Handheld Scanners


Using hand scanners are much more expensive but like all equipment the more features there are the more you will pay. With the high-end handheld scanners, you will be paying more than $100 and even much higher than that. The first advantage of having a handheld tool is that most of them come with their own battery pack, therefore, the data can store on the handheld scanner.

They can also analyse manufacturer specific DTC’s and use the data to print from the computer showing graphs. They are able to analyse not only what is happening with the engine but can check things like the ABS breaks and the airbags.

A lot of the top handheld scanners have also got inbuilt functions such as what the probable solution could be and make it a lot easier for the mechanic to fix. Some of them have a database of more than 20 million fixes that they can draw from.

They also have the ability to store different vehicles that have been scanned and all these features are not available with the ELM327 which you need to connect to the computer. With the hand held devices, you have the option of doing all the computer analyses and printing of graphs away from the car.

It is a good tool to have for the do-it-yourself mechanic who not only can diagnose what the problem is but also has the option of recalling which is the most probable cause.

So even though they are a lot more expensive they are more versatile and can store data that can be directly called up which is not possible using an ELM327 code reader.

Why use scanners?…

Having a diagnostic tool that is readily available gives the owner the piece of mind if something should show on the dashboard they can easily check whether the problem is serious and the car needs immediate attention or if it can be attended to later.

For this purpose, there should be no need to invest in very expensive equipment and the ELM327 will be suitable. Most people have smartphones, therefore, connecting to the car on board computer system is not difficult. The equipment is small and simple to store in the car.

If you are the person that likes to do the mechanics yourself then probably a more expensive handheld diagnostic scanner will be better because of the ability to have the facility of storage capacity and ability to give solutions to certain faults. The top range handheld scanners also have the ability to diagnose other functions like the brakes and airbags.

Scanners also have the capacity to do real-time performance checking of the vehicle which will show the mechanic exactly where to start repairing in order to get a better performance.

Fuel Injectors are extremely sensitive to oxygen and fuel mixtures and if these are not correct then the scanner will quickly diagnose that the ratio is incorrect.

By seeing this the mechanic can adjust or replace whatever is necessary to get the best fuel consumption.

In countries that fuel emission inspections are done at certain times have an engine light on will fail the car from these inspections.

Car diagnostics can have inspection and maintenance readiness tests done and if it is found that the power train is not properly fixed or has a fault will mean that the car will fail.

If the owner has the option of running the tests themselves and passing them the technician will see a clean scan at the inspecting department.

The owner does, however, have to fix any problems that there might be or else it will be detected by the technician’s scanner but at least you will have the peace of mind that the car will pass the emissions test.

Other useful features of doing diagnostics on the cars that you own are that you can have service warnings put in place and you will be notified that the car is ready for a service.

The GPS functions that the diagnostic scanners have can help you log accurately the mileage that has been done and what the fuel consumption is and you can know exactly when there is a problem.

This way it can save you a substantial amount of money and the scanner basically pays for itself.

Which interface to Choose?…

This is very much a personal choice and how much car maintenance the person actually does.

If it is to monitor the performance of personal vehicles only which is perfect for the DIYers and using the information to keep track of how the engine is performing and what needs maintenance then a simple system such as the ELM327 is sufficient.

It is not expensive and you are utilising tools that you already have the added advantage of being able to download software for free.

The interface that is displayed on the computer or mobile device is very informative with diagnostic information that is very useful to make sure that the car is running well and at its best performance. This information can be logged and exported as .csv files for you to keep on record.

If that is all the information that you need then the ELM327 has the capacity to.

If however there are more complex problems to solve on a daily basis then a more robust system like the hand held scanners need to be considered.

These are designed to be able to be more versatile and have added features that are required when someone is doing the daily maintenance. They generally have the ability to diagnose other functions in the vehicle.

Handheld scanners are also more robust and do not require the use of any other equipment such as a computer or a mobile device making it more practical to use in a workshop environment.

Different Software Interfaces

software-applications-for-elm327-interfaceThe problem with buying handheld scanners is that you have a dedicated software package even though they generally cover all the functions and features that you require.

These you will need to pay for and it is an added cost to the overall expense. This, however, is outweighed by the amount of money that can be saved by having an efficient running vehicle.

The top hand scanners do however have the software that helps the mechanic with troubleshooting and repairing the fault.

By using ELM327 there is a lot of software that is free to download but requires some research so that you can download the software that will give you the information that will best suit you.

The great thing about having mobile app software is that there are add-ons which come in useful such as fuel consumption graphs. That way you have real-time information of how best to conserve fuel. These can be displayed as graphs on your smartphone or tablet.


That makes it more fun for the DIYers and at the same time they have the diagnostic tool to fix the problem if there should be one.

The software that is designed for the smartphones such as iPhone or Android do have very informative screens and are very similar to what you will see on a computer using the hand held scanner software.

So even though you do not have the full package and it is certainly nowhere near to workshop type scanners which cost thousands it can certainly help the do-it- yourself mechanic do their own repairs which before was out of reach partly because of the expense.



With the advent of the OBD computer systems, it has become a lot easier for every person to be able to do diagnostics on their car if they have the required equipment.

At first, it was only possible for dealers to afford the expensive diagnostic scanners but as technology has progressed so has the scanner technology and made it more affordable for all mechanics and DIYers to have the necessary scanning tools.

With the advent of the ELM327 interface has made it possible to use with mobile devices and across all operating systems has made diagnostics much more accessible. It is not at the moment at the point where it is as good as the more advanced scanners but is a useful diagnostic tool that has its place in amongst car enthusiast.

Even though it is marketed as a diagnostic tool for the do-it-yourself mechanic it can also be a useful tool for the experienced mechanic who needs to go to a breakdown away from the standard scanners. It will provide the diagnostics that will allow the mechanic to know where to find the fault.

With the price that you pay for an ELM327 interface and the features it has it can be used for normal type servicing and some other useful uses as already mentioned.

However for the car dealer or workshop that requires to repair and service a multitude of vehicles the larger standard scanners still provide much more detailed diagnostics which ensures that the vehicle is performing at its best.

Lastly which is the right interface to use is very dependent on what the user is requiring the diagnostic equipment for and the overall purpose. If it is just for monitoring and gathering information then the ELM327 is more than adequate.

If however technology keeps progressing at the rate it is there will come a time when diagnostic interfaces such as ELM327 will be just as technically advanced as the standard scanners are today.

Related Sources: 1 | 2 | 3

ELM327 Interface Reviewed – What You Need to Know
4.3 (85.56%) 18 votes

2 Responses to ELM327 Interface Reviewed – What You Need to Know

  1. Good review. It’s hard to find genuine ELM327 today. Most are clones like on eBay. Got one from totalcardiagnostics.com/elm327 and found it does everything needed for all Android OBD apps I’ve used including DashCommand, ScanMaster, Torque.

  2. We used different ELM327 units throughout years. There is BAFX, etc on Amazon. Still found totalcardiagnostic elm327 best in overal. How? Rarely has compatability issues which others exibit.

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