Home » Blog » ELM327: All You Need To Know [Updated May 2019]

ELM327: All You Need To Know [Updated May 2019]

Table of Contents

Introduction to ELM327 Interface

Modern cars come with an electronic component that allows users to connect and run a variety of diagnostic programs. The ELM327 interface serves as a connector that lets you connect your car to computers, tablets, and smartphones. You can connect virtually any Android, Windows, or iOS device with the help of the ELM327 interface.

Up until 1996, car manufacturers had their OBD standards and protocols. Auto mechanics were forced to keep up with the latest trends in technology, which made diagnostics very complicated.

The ELM327 Interface lets mechanics perform diagnostics using cost-effective hardware. Having a universal interface helps mechanics address common automobile issues effectively.

Among many types of lơ-cost OBD tools is the ELM327 microcontroller.

ELM327 translates and relays data from the car’s Electronic Control Unit (ECU) to a Windows, Mac OS, Android or iOS device.
Credit: commons.wikimedia.org

ELM327 Adapter: ELM327 Wifi vs. ELM 327 Bluetooth vs. ELM327 USB

Bluetooth ELM327 adapters are capable of transmitting radio waves between a car and ELM327-compatible devices. File transfers are hassle-free using Bluetooth, and you do not have to plug in wires. Considering very little data is transferred using the ELM327 interface, data transfer speeds are not very relevant.

Most users prefer wi-fi ELM327 adapters, and you also have more options available for purchase. The technology does suffer from a significant issue when it comes to connecting to Android devices. If you want to use an Android device, you can’t stay connected to the internet when the ELM327 interface is in use.

If you own an Android device, your options are limited to Bluetooth adapters only if you want uninterrupted internet connectivity. iOS owners, on the other hand, can choose from either Bluetooth or Wi-Fi options. You always have the option of purchasing a wired adapter as well if power consumption is an issue for you.

Best ELM327 Adapter: Editor’s Top 3 Picks Comparison Table

Best ELM327 BluetoothBest ELM327 WIFIBest ELM327 USB
Vgate iCar Pro Bluetooth Adapter
Vgate iCar Pro Bluetooth Adapter
wsiiroon
wsiiroon ELM327 Wifi Adapter
OHP ELMconfig Forscan OBD2 USB Adapter[
OHP ELMconfig Forscan OBD2 USB Adapter
Customer Rating
4.34.3 / 5
3.93.9 / 5
4.74.7 / 5
PriceVgate iCar Pro Bluetoothwsiiroon priceOHP ELMconfig Forscan OBD2 USB Adapter price
Pros- Real-time ECU sensor data
- Supports manufacturer-specific error codes
- Freeze frame data
- Android and iOS
- Check engine lights, vehicle sensor data
- Supports non-US vehicles
- Android and iOS devices
- Supports third-party apps
- Setup with Forscan, FoCCUS
- Compatible with all cars and light trucks
- Live data management
Cons- Monthly subscription required
- Not compatible with Bimmercode
- No Bluetooth support
- Not compatible with large trucks
- No Bluetooth or Wi-Fi Support
- Not compatible with heavy trucks
Bottom lineVgate iCar is definitely worth the investment with its guaranteed compatibility and a large number of functions.If you want a one-stop solution for all your diagnostic needs, wsiiroom adapter is a recommended option considering its price and value for money.The OHP adapter is specifically geared towards the owners of Ford, Mazda, and Lincoln owners.

Best ELM327 BLUETOOTH Adapters Review

1
Mestart Bluetooth Adapter for Android Devices

Mestart Bluetooth Adapter
Mestart Bluetooth Adapter for Android Devices
4.14.1 / 5
Mestart Bluetooth Adapter is ideal for anyone looking for an affordable ELM327 Interface device for Android.

Mestart Bluetooth Adapter is perfect for OBD2 and EOBD cars. The Bluetooth technology in the device makes connectivity a breeze with no need for additional wiring. The Mini Interface device also boasts of reliable Bluetooth coverage.

Usability is something the manufacturer prioritized when creating the Bluetooth adapter. Plug the device into your car’s OBD2 port, fire up Bluetooth, and you are ready to connect.

The adapter displays critical sensor data like engine speed, airflow, fuel pressure, and more.


Mestart Bluetooth Adapter is not compatible with iOS.
———

Pros

  • Wireless connectivity
  • Multi-Protocol Support
  • Tracks Long Term Fuel Trim
  • Fuel System Diagnosis
  • Displays Absolute Throttle Position

Cons

  • Not compatible with iOS
  • Connectivity issues on some cars

Compatible Apps:

  • Torque Pro
  • OBD Car Doctor

Mestart Bluetooth Adapter is ideal for anyone who is looking for an affordable ELM327 Interface device for Android. It can be used for diagnosis and monitoring your car’s systems.

2
Foseal Bluetooth OBD2 Scanner for Android and Windows Devices

Foseal
Foseal Bluetooth OBD2 Scanner for Android and Windows Devices
44 / 5
Foseal’s Bluetooth OBD2 Adapter is capable of reading error codes that may arise out of problems in your car.

Foseal’s Bluetooth OBD2 Adapter is capable of reading error codes that may arise out of problems in your car. Users can monitor current sensor data and check for underlying issues before consulting a mechanic.

The high-quality adapter is compatible with all gasoline vehicles that support OBD2. However, diesel vehicles, hybrids, and trucks with 24V voltage or higher are not compatible with the adapter.

The Foseal adapter is compatible with Android and Windows devices but does not support iOS. You can use it to check engine coolant levels, oil temperature, air flue, speed, and other essential data.

Foseal’s Bluetooth OBD2 Adapter is capable of reading error codes that may arise out of problems in your car.
You can use Foseal to check engine coolant levels, oil temperature, air flue, speed, and other essential data.
———

Pros

  • Over 3000 code definitions
  • Displays current sensor data
  • Erasable trouble codes
  • Oxygen sensor voltage reading
  • Vehicle speed monitoring
  • Smooth UI

Cons

  • Not compatible with iOS
  • Low wireless coverage

Compatible Apps:

  • Torque Pro
  • DashCommand

The Foseal Bluetooth adapter is ideal for DIY mechanics and car owners alike. You can use it to monitor your car for any underlying issues that need addressing.

3
Vgate iCar Pro Bluetooth 4.0 ELM327 OBD2 Adapter for iPhone iPad and Android

Vgate iCar Pro
Vgate iCar Pro Bluetooth 4.0 ELM327 OBD2 Adapter for iPhone iPad and Android
4.34.3 / 5
Vgate’s OBD2 fault code reader is one of the best companions any car owner can have

Vgate’s OBD2 fault code reader is one of the best companions any car owner can have. If you can’t figure out what is wrong with your car engine plug in the adapter and you will be able to identify issues with your car’s engine.

The plug-and-play functionality makes setting up the Vgate adapter extremely simple. The software is compatible with a large number of OBD2 apps which lets you get more functionality out of the device.

The power-saving feature makes the Vgate iCar Pro an ideal device. All you need to do is plug in the Bluetooth adapter and forget about it. Setting it up is just as simple with apps available for both Android and iOS that you can use to operate the device.

Vgate’s OBD2 fault code reader is one of the best companions any car owner can have.
Vgate iCar Pro is available for both Android and iOS.
———

Pros

  • Real-time ECU sensor data
  • Supports manufacturer-specific error codes
  • Can display freeze frame data
  • Compliant with all OBD2 and EOBD compliant devices
  • Strong Bluetooth coverage

Cons

  • Monthly subscription required to use the official app
  • Not compatible with Bimmercode

Compatible Apps:

  • Torque
  • OBD Auto Doctor

While you do have to pay a monthly subscription fee to use all of the premium features of the app, the professional software is definitely worth the investment. With guaranteed compatibility and a large number of functions, you do not want to miss out on the iCar Pro.

Best ELM327 WIFI Adapters Review

1
FOXWELL FW601 WIFI ELM327 OBD2 Adapter for iPhone, iPad & Android

FOXWELL FW601
FOXWELL FW601 WIFI ELM327 OBD2 Adapter for iPhone, iPad & Android
4.14.1 / 5
Foxwell FW601 is capable of working on all vehicles in the USA as long as they are OBD2 compliant and support Wi-Fi.

Foxwell FW601 Wi-Fi based ELM327 adapter is a cost-friendly option for car owners who want a product that is compatible with both Android and iOS. Unlike other Bluetooth options, you need to own a car that was produced in 2000 or after to make use of the Wi-Fi technology.

The Foxwell adapter is capable of working on all vehicles in the USA as long as they are OBD2 compliant and support Wi-Fi. If you are looking for in-depth vehicle analysis, the vehicle analyzer app will let you identify and diagnose problems instantly.

To get started, all you need to do is download the mobile app and pair it with your adapter. It is much better than most other car adapters available mostly because of its usefulness and pool of features.

The Foxwell adapter is capable of working on all vehicles in the USA as long as they are OBD2 compliant and support Wi-Fi.
Foxwell’s FW601 is a cost-friendly option for car owners who want a product that is compatible with both Android and iOS.
———

Pros

  • Works with most vehicles released in the US
  • Wi-Fi coverage is great
  • Vehicle Analyzer app allows in-depth analysis
  • One-year warranty
  • Works on both Android and iOS

Cons

  • Does not support Bluetooth
  • Compatibility limited to cars from 2000 or later

Compatible Apps:

  • DashCommand
  • InCarDoc Pro

If you are looking for a Wi-Fi adapter that supports most popular vehicles and is easy to set up, the Foxwell is one of the best choices available for consumers. The feature-rich mobile app is user-friendly, and the setup process is a breeze.

2
Vgate iCar2 WiFi OBDII ELM327 Interface for iPhone, iPad, and Android

Vgate iCar2
Vgate iCar2 WiFi OBDII ELM327 Interface for iPhone, iPad, and Android
4.14.1 / 5
The Vgate iCar2 is a best-in-class Wi-Fi adapter that supports not only most US cars but also European and Asian vehicles.

The Vgate iCar2 is a best-in-class Wi-Fi adapter that supports not only most US cars but also European and Asian vehicles. With real-time engine data reading and a long list of visible statistics within the mobile app, iCar2 is worth a look.

If you do not want to be scammed by shady mechanics, the interface can help you take a quick look at problems with your car. To top it off, the plug-and-play mechanic makes it straightforward for owners to set up the device with their Wi-Fi enabled phones.

The Vgate iCar2 is a best-in-class Wi-Fi adapter that supports not only most US cars but also European and Asian vehicles.
Vgate iCar2 allows car owners to set up the device with their Wi-Fi enabled phones.
———

Pros

  • Plug and Play compatibility
  • Supports a suite of third-party apps
  • Can read thousands of DTCs and manufacturer-specific codes
  • Compatible with iOS and Android
  • One Year Replacement Warranty

Cons

  • Not compatible with heavy trucks
  • Wi-Fi coverage drops off at long distances

The iCar2 is one of the best plug-and-play ELM327 interface adapters that allows you to diagnose problems with your car engine efficiently.

3
wsiiroon’s ELM327 Wifi OBDII Adapter for Android and iOS

wsiiroon
wsiiroon’s ELM327 Wifi OBDII Adapter for Android and iOS
3.93.9 / 5
wsiiroon’s ELM327 interface is an all-in-one solution for nearly every car type.

wsiiroon’s ELM327 interface is an all-in-one solution for nearly every car type. You can plug the device into your vehicle and expect full-fledged compatibility: the manufacturer American, Asian, and European cars, which is very impressive considering the price.

The device is effortless to set up and offers professional results with its minimalistic and user-friendly UI. You can also use third-party apps for in-depth analysis.

wsiiroon’s ELM327 interface is an all-in-one solution for nearly every car type
Wsiiroon ELM327 uses the free program software, which allows you to use your PC and mobile phone.
———

Pros

  • Can check engine lights, vehicle sensor data and more
  • Smart scanning feature to monitor system status
  • Compatible with all major Android and iOS devices
  • Supports third-party apps
  • Supports non-US vehicles

Cons

  • No Bluetooth support available
  • Not compatible with large trucks

Compatible Apps:

● DashCommand
● FourStroke

If you want a one-stop solution for all your diagnostic needs, the wsiiroom adapter is a recommended option considering its price and value for money.

4
Gemwon ELM327 Wifi OBDII Wifi Adapter for Android and iOS

Gemwon ELM327 Wifi
Gemwon ELM327 Wifi OBDII Wifi Adapter for Android and iOS
4.44.4 / 5
Gemwom’s ELM327 interface Wi-Fi adapter is one of the best Android/iOS devices that lets you scan over 3000 trouble codes in a matter of seconds.

Gemwom’s ELM327 interface Wi-Fi adapter is one of the best Android/iOS devices that lets you scan over 3000 trouble codes in a matter of seconds. The WiFi adapter works with all kinds of consumer cars from brands like Honda, BMW, Ford, and dozens of other manufacturers.

One of the USPs of the device is the compatibility with 12V petrol cars, which is quite impressive considering most adapters work with gasoline vehicles only. Users can plug in the adapter and check stats like fuel system status, air flow rate, and other stats instantly.

Gemwom works with all kinds of consumer cars from brands like Honda, BMW, Ford, and dozens of other manufacturers.
Gemwom lets you scan over 3000 trouble codes in a matter of seconds.
———

Pros

  • Self-diagnosis tools
  • 18-month warranty period
  • Works with petrol vehicles
  • Compatible with all Android and iOS smartphones
  • Displays real-time sensor data

Cons

  •  Does not support Bluetooth
  • The configuration process is slightly cumbersome

Gemwom’s Wi-Fi adapter is one of the most versatile when it comes to compatibility. With support for vehicles from global manufacturers, you can’t go wrong with what the ELM327 interface adapter has to offer.

5
KOBRA Wireless OBDII Wifi Adapter for Android and iOS

KOBRA
KOBRA Wireless OBDII Wifi Adapter for Android and iOS
3.63.6 / 5
OBD2 of KOBRA can scan not only any generic error code but also manufacturer-specific error codes that may be triggered by your car.

KOBRA is one of the best when it comes to auto diagnostics. Their OBD2 can scan not only any generic error code but also manufacturer-specific error codes that may be triggered by your car.

All you need to do to get in-depth stats is to connect your Android, iOS, or Windows device and follow the setup instructions. There are several free and paid apps available to diagnose any problems your car may be facing.

KOBRA’s ELM327 interface is one of the few devices available that offers support for Windows.
KOBRA works with all US vehicles models from 1996.
———

Pros

  • Works with all US vehicles from 1996
  • Compatible with Windows, Android and iOS devices
  • Supports small trucks
  • Over 3000 code definitions
  • 1-year money back guarantee

Cons

  • Does not support Bluetooth
  • No support for European and Asian cars

Compatible Apps:

  • DashCommand
  • OBD Car Doctor

With most manufacturers focusing on Android and iOS only with their Wi-Fi adapters, KOBRA’s ELM327 interface is one of the few devices available that offers support for Windows.

Best ELM327 USB Adapters

1
VINT-TT55502 ELM327 USB Adapter For all Windows

VINT-TT55502
VINT-TT55502 ELM327 USB Adapter For all Windows
4.44.4 / 5
If you are looking for a USB adapter, VINT offers its ELM327 device that is compatible with all Ford, and Mazda cars released since 1996.

If you are looking for a USB adapter, VINT offers its ELM327 device that is compatible with all Ford, and Mazda cars released since 1996. The adapter works on both light trucks and vehicles which is quite appealing considering most of these tools do not support light trucks.

The interface is compatible with MS-CAN switch, and it can be hooked up to ELMconfig or FoCCCus software. Users can read, code, and erase live data with minimal effort, which is great for beginners.

If you want in-depth data for specific components, the VINT USB adapter is one of the best choices out there.

Pros

  • Can read and erase live data with ease
  • Includes all common service procedures
  • DFP force regeneration
  • Modifiable ECU parameters
  • Individual component activation.

Cons

  • Does not work with heavy trucks
  • Works with US models only
  • Limited to Ford and Mazda vehicles

Compatible Apps:

  • FF2
  • Forscan

If you own a Ford or a Mazda, this should be your go-to option. The ELM327 interface is user-friendly, and the setup process is hassle-free. Anyone who wants to diagnose problems with their engine should consider picking the VINT adapter up right away.

2
OHP ELMconfig Forscan OBD2 USB Adapter for Ford Car Diagnostics on Windows

OHP ELMconfig Forscan
OHP ELMconfig Forscan OBD2 USB Adapter for Ford Car Diagnostics on Windows
4.74.7 / 5
OHP ELMconfig Forscan can be used to diagnose a large number of problems that are commonly seen in car engines

The OHP ELMconfig Forscan OBD2 is one of the best adapters for Ford, Mazda, and Lincoln owners. Even though the adapter is compatible with cars and light trucks only, it covers almost the entire lineup of all three manufacturer’s offerings in the industry since 1998.

Even though the ELMConfig Forscan OBD2 adapter does not support Bluetooth or Wi-Fi, you get a very consistent 500kbits/s of connectivity. The operating speeds are more than sufficient, making it one of the best USB adapters available right now.

The DIY diagnostic tool can be used to diagnose a large number of problems that are commonly seen in car engines. If you want to configure the as-built data of your car, you can do that as well with the vast customization features.

Pros

  • Seamless setup with Forscan, FoCCUS and other popular software
  • Compatible with all cars and light trucks from Ford and Mazda
  • Access to all modules
  • Supports all US models since 1996
  • Live data management

Cons

  • No Bluetooth or Wi-Fi Support
  • Not compatible with heavy trucks

Compatible Apps:

  • Forscan
  • FoCCCus

The OHP adapter is specifically geared towards the owners of Ford, Mazda, and Lincoln owners. If you own a car from any of the three listed manufacturers, you should consider acquiring an ELM327 interface by OHP for DIY diagnosis.

ELM327 RS232

ELM327 RS232 or ELM327 Series adapters are hard to come by these days because they are being phased out in favor of USB, Bluetooth and Wi-Fi interfaces. That said, if you get your hands on one you may still be able to pull and clear codes from the engine as well as view live data.

OS Compatibility of ELM327 Wi-Fi, Bluetooth, USB & RS232

Windows (PC) SoftwareMac OS SoftwareAndroid AppiOS App
ELM327 RS232YesYesN/AN/A
ELM327 USBYesYesN/AN/A
ELM 327 BluetoothYesN/AYesN/A
ELM327 Wi-FiYesYesYesYes

ELM327 Apps: What Are the Best Ones For iPhone Or Android?

You can do anything with an ELM327 interface, even using aphone or tablet

If you are using a phone or tablet then your device needs to have an ELM327 app
———

ELM327 adapters are not stand-alone devices. They are basically dongles that pair with a computer device in order to run diagnostics. If you are using a phone or tablet then your device needs to have an ELM327 app before you can do anything with an ELM327 interface.

So what are the best ELM327 apps on the market right now? Below is a brief look at the apps that work best on iOS and Android devices.

ELM327 Apps for iPhone

Car Scanner ELM OBD2

Car Scanner ELM OBD2 works with all OBD2-compliant vehicles. It connects to mobile devices via Bluetooth and Wi-Fi, which makes it perfect for mobility. More importantly, this app features diagnostic functions, a trip guide and car performance tracker.

With it you can view and clear engine codes. By doing so it allows you to turn off the Check Engine Light. Each code comes with a description thanks to the rich library of code definitions.

Additionally, the app displays tons of data, including custom PIDs, Mode 6, emission readiness status and live sensor data. The latter is presented as gauges that you can use to view the performance and fuel efficiency of your car.

Download Car Scanner ELM OBD2

OBD Auto Doctor

Compared to other ELM327 apps, OBD Auto Doctor is perhaps the best at information gathering and reporting. Besides reading and clearing ECU codes, this application can pull a car’s VIN, CVN, freeze frame data, emission status and live data.

While the ability to reset the CEL is the highlight of this app, its live data is just as important. With it you can know how your engine is performing. Additionally, it helps you plan better thanks to its fuel economy gauges that show things like the amount of gas remaining, distance to empty, miles per gallon and so much more.

Download OBD Auto Doctor

Carista OBD2

Carista is one of the most popular OBD2 apps out there, and rightfully so. It not only allows you to read/clear ECU trouble codes and turn off the Check Engine Light, but it also supports checking of other systems.

More specifically, you can read and erase codes from the SRS and ABS systems. With the premium version of the app you can also do service reset, EPB retraction and TPMS functions

Download Carista OBD2

ELM327 Apps for Android

Torque Pro

Torque Pro can read and clear both current and pending trouble codes from the engine. In other words it can help you determine the cause of the Check Engine Light and even turn off the light.

On top of that, this ELM327 app monitors sensors, including the very important O2 sensors. With data from those sensors you will know whether your car will pass federal and state emissions.

One of the standout features of Torque Pro is that it has a built-in dynamometer for displaying live data. Some of the information that you will get include torque, horsepower, fuel trim, RPMS, transmission temp and many more that show your car’s efficiency and fuel economy.

Download Torque Pro

OBD Fusion

OBD Fusion offers three main functions. First it allows you to turn off the Check Engine Light by reading and clearing engine trouble codes.

Secondly, the app has a built-in fuel economy monitor that helps you plan your trips. It shows such information as amount of fuel, miles per gallon, distance to empty and so much more.

Finally, OBD Fusion offers tons of gauges and graphs that show you how your car is performing in real-time. You can view information like mass air intake, RPM, acceleration, speed, engine temp etc.

Download OBD Fusion

DashCommand

DashCommand excels at three things. The first is reading and clearing engine codes. With a built-in database of code definitions, you can use the app to turn off the Check Engine Light.

Secondly, DashCommand is an excellent monitoring tool for your fuel economy and car performance. It has gauges that display fuel flow rate, fuel level, amount of fuel left in tank, time to empty, distance to empty, torque, braking, acceleration, engine speed, boost vacuum etc.

Finally, this ELM327 app works as an emission status monitor. It lets you run I/M readiness tests to determine whether your car will pass emission checks.

Download DashCommand

ELM327 Software Packages for PC

ELM327 has created OS-specific diagnostic software that caters for users of Windows, Mac OS X, Linux and pretty much any other operating system

Thanks to the multiple OBD2 software, you can work
seamlessly with ELM327 on PC.
Credit: commons.wikimedia.org

If you would rather use your ELM327 adapter with a PC you can do so thanks to the multiple OBD2 software that work seamlessly with ELM327. Many developers have created OS-specific diagnostic software that caters for users of Windows, Mac OS X, Linux and pretty much any other operating system.

OBD2 Software for Windows

FORScan

FORScan is compatible with all versions of Windows starting from Windows 2000 all through Windows 10. This ELM327 covers Ford, Lincoln, Mazda and Mercury cars and light trucks.

With it you can read and clear generic as well as manufacturer-specific codes that are related to the engine. As such, it allows you to reset the Check Engine Light.

Additionally, the software can read sensor data and display it either as text or PIDs. It supports service procedures as well as test diagnostic procedures.

EngineCheck

EngineCheck also works on Windows 2000 and all newer versions of the OS.Contrary to FORScan that’s only compatible with a few brands of cars, this particular ELM327 software covers all gas-powered cars that were manufactured from 2001 and diesel cars that were made from 2004.

In terms of functionality, EngineCheck allows you to read and clear engine codes. It therefore makes it possible to reset the Check Engine Light. Additionally, the software can display freeze frame data, live sensor data, on-board test completion status and fuel system status.

Freediag

freediag is a bit different from other ELM327 software for Windows. Why do I say so? Because currently it only supports a command line interface (CLI). If you know your way around CLI you’ll find this software quite interesting.

It’s primarily designed to diagnose and reset the Check Engine Light. It can do so on virtually any OBD2-complaint car. In total, this software supports 5 main protocols (ISO 9141, ISO 9141-2, ISO 14230, SAE J1850 (PWM and VPW) and SAE J2818/KWP1281/VAG) as well as the Mercedes Gearbox Protocol.

OBD2 Software for Mac OS X

Goserial

Goserial is a nice little OBD2 software that’s completely free. It’s basically a terminal interface that lets you read and clear Check Engine Light and emission-related codes. You can use goserial on any Apple computer running Mac OS X 10.4 or a newer version

ELM327 Firmware

Your best bet is sticking with the official versions of ELM327
One thing that confuses many ELM327 buyers and users is the firmware version used
———

One thing that confuses many ELM327 buyers and users is the firmware version used. To date there are only 12 official versions, namely 1.0, 1.0a, 1.1, 1.2, 1.2a, 1.3, 1.3a, 1.4,1.4b, 2.0, 2.1 and 2.2.Although all the versions are still in circulation, the most common are v1.3 all through v2.2.

Unless you’re an advanced user of ELM327 diagnostic tools, chances are you won’t be able to tell the difference between these versions. They all have the same basic diagnostic functions. However, like most other techtools, the newer the version the more stable it will be

Watch Out For Clones and Fakes

There are several cloned and fake versions of the original ELM327. What happened is that when ELM Electronics first introduced v1.0 they did not copy protect it. As a result, many different unofficial versions have been created by other manufacturers and made available for users.

While some clones are fairly stable, others are worryingly buggy. Even so, your best bet is sticking with the official versions of ELM327. Do not be tempted to pick a version that sounds like “the latest”.

For example, there are some manufacturers who claim to have upgrade the code used in v1.4. Those manufacturers went ahead and released v1.4a and v1.5. In truth both v1.4a and v1.5 are in fact copies of v1.2 masquerading as newer versions. So if you buy them you’ll likely get a device that still has the same bugs and issues associated with v1.2.

What Is An ELM327 Interface?

ELM Electronics makes the chips that ELM327 devices run on

An ELM327 interface operates based on three sub-parts.
Credit: flickr.com

Although ELM Electronics makes the chips that ELM327 devices run on, other companies take those chips and use them to make ELM327 adapters. Each of those adapters is what is called an ELM327 interface.

It’s called an interface because it acts as a link between a vehicle’s on-board computer(ECU) and your external computer (smartphone, tablet or PC). With it you can view real-time data from the ECU, run some diagnostics and read/clear codes that are associated with the Check Engine Light.

Generally, an ELM327 interface operates based on three sub-parts. The first is the ELM327 chip. This is an integrated circuit that’s rated at 4MHz. It is the brain behind the whole device onboard its purpose is to convert data from the ECU to a format that can be understood by modern computing devices.

The second sub-part is the set of electric voltage adaptors. Their primary function is to identify the various on-board systems of a car using their unique voltage properties. For example, an ELM327interface is able to distinguish the EVAP system from the fuel system using its electric voltage adaptors. They are usually given as protocols like CAN, K/L or PWM/VPN.

Finally, there is a set of voltage adaptors for PC. These ones make it possible for an ELM327 adapter to adapt its electrical levels to those of a computer device (PC, smartphone or tablet). By doing so the adapter and the computer can successfully communicate.

What Functions Can ELM327 Interface Offer?

With a bi-directional diagnostic tool like ELM327, you can view the definition of each code and determine the problem

ELM327 allows you to read and clear generic as well as manufacturer-specific codes.
———

I have mentioned from a general point of view that ELM327 allows you to view real-time data from the ECU, run some diagnostics and read/clear codes. I should add that as an OBD2 adapter, ELM327 works with a diagnostic app/software.

What you do is that you install the app/software on your smartphone/tablet/PC and use it as a diagnostic platform.The exact range of functions that you will get depends on the app or software you are using. I will talk more about that later in this post, but for now here are the most common functions of ELM327:

Diagnostic Trouble Codes (DTCs)

As a bi-directional diagnostic tool, ELM327 allows you to read and clear generic as well as manufacturer-specific codes. You can view the definition of each code and determine whether the problem needs you to take the car to the shop or if you can handle it the DIY way. Note that when you clear ECU codes you can turn off the Check Engine Light (CEL).

Diagnostic Data

In addition to codes, you can view PIDs and emission data. PIDs are graphical representations of sensor data. By observing them you can tell whether your car’s on-board systems are performing normally or if there’s an abnormality that requires your attention. Emission data, on the other hand, indicates whether the car will pass federal and state smog tests.

Live Data

Diagnostic data is great for pinpointing problems. Live data, on its part, shows you the performance of your car. ELM327 provides real-time data that you can use to analyze things like engine performance and fuel economy. Here’s a list of the live data that you can view:

• Absolute Throttle Position
Air Fuel Ratio
• Average Trip Speed
• Barometric Pressure
• Command Equivalence Ratio
• CO2 Emissions
• Distance Traveled Since Clearing ECU Code
• EGR Commanded
• Engine Coolant Temperature
• Engine Load
• Engine RPM
• EVAP System Vapor Pressure
• Fuel Cost
• Fuel Level
• Fuel Rail Pressure
• Fuel Used (trip)
• GPS Altitude
• GPS Latitude
• GPS Satellites
• Intake Air Temperature
• Kilometers Per Liter
• Miles Per Gallon
• O2 Volts
• Relative Throttle Position
• Speed
• Timing Advance
• Transmission Temperature
• Trip Average MPG
• Trip Time
• Voltage (Control Module)
• Accelerator Pedal Position
• Ambient Air Temperature
• Barometer
• Catalyst Temperature
• Cost Per Mile
• Distance to Empty Fuel Tank
• Distance Traveled with Check Engine Light On
• EGR Error
• Engine kW
• Engine Oil Temperature
• Ethanol Fuel Percentage
• Exhaust Gas Temperature
• Fuel Flow Rate
• Fuel Pressure
• Fuel Trim Bank
• GPS Accuracy
• GPS Bearing
• GPS Longitude
• Horsepower
• Intake Manifold Pressure
• Mass Air Flow
O2 Sensor
• Relative Acceleration Pedal Position
• Run Time Since Engine Start
• Throttle Position
• Torque
• Trip Average KPL
• Trip Distance
• Turbo Boost and Vacuum Gauge
• Volumetric Efficiency

Data Management

You can log both diagnostic data and real-time (live) data to your phone, tablet or PC. ELM327 gives you the option to receive the data via Text file or email. However you prefer, you can share it with people who understand diagnostics better in case you need someone else’s opinion.

What Protocols Are Supported By ELM327 Interface?

ELM327 is fully compatible with all types of protocols.

The 327 version is the most popular because it supports all OBD2 families of protocols

ELM327 is not the only ELM interface around. Its predecessors, the ELM320, ELM322 and ELM323 are still very much available for purchase and use. However, the 327 version is the most popular because it supports all OBD2 families of protocols.

ELM320 supports only one type of protocols; the PWM. The same goes for ELM322 and ELM323 which only support VPN and KWP protocols respectively. On its part, ELM327 is fully compatible with all types of protocols.

More specifically, it works with CAN, KWP, PWM, and VPN. That translates to all OBD2 protocols. Here’s the list:

  • ISO 15765-4 CAN (11 bit, 500 kbit/s)
  • ISO 15765-4 CAN (29 bit, 500 kbit/s)
  • ISO 15765-4 CAN (11 bit, 250 kbit/s)
  • ISO 15765-4 CAN (29 bit, 250 kbit/s)
  • ISO 14230-4 KWP (5 baud init, 10.4 kbit/s)
  • ISO 14230-4 KWP (fast init, 10.4 kbit/s)
  • SAE J1850 PWM (41.6 kbit/s)
  • SAE J1850 VPW (10.4 kbit/s)
  • ISO 9141-2 (5 baud init, 10.4 kbit/s)
  • SAE J1939 (250kbit/s)
  • SAE J1939 (500kbit/s)

To put it simply, ELM327 is compatible with practically all OBD2 cars that are made or sold in the US. So, as long as your car is not a 1995 or older model you may use an ELM327 adapter for its diagnostics.

How To Use ELM327 Interface

The newer ELM327 adapters use Wi-Fi, Bluetooth or USB to connect the interface to your phone.

Althought there are some ELM327 interfaces that differ in shape, size and
design, they all start by plugging your ELM327 adapter to your car’s OBD2 port.
Credit: flickr.com

Although you may find some ELM327 interfaces that differ in shape, size, and design, they generally follow the same procedure for connection and use. Start by plugging your ELM327 adapter to your car’s OBD2 port.

From there connect the interface to your phone, tablet or PC. The older ELM327 adapters use a serial port but newer models use either Wi-Fi, Bluetooth or USB. Later on I’ll explain more on these connections and the pros and cons of each.

Make sure that the phone, tablet or PC that you’re using already has anELM327 app or ELM327 software installed. These are basically OBD2 apps or software that help you run diagnostics. I’ll talk more about them as well, so read on to find out how they work.

Once you have made those two connections (to the car and to your computer device) run the OBD2 application. Next, start the car’s ignition and ensure that the engine indicator is lit (on the dashboard). Most ELM327 software will connect automatically or at least they will ask you to connect.

From there you can start collecting data from the ECU while viewing them on your phone or PC. Be sure to observe the LEDs on the ELM327 adapter.

The red LED indicates that the adapter is powered on. On the other hand, the yellow LED is referred to as Tx OBD. It flashes to indicate that there is data transfer from the ELM327 interface to the car’s ECU and from the computer device to the interface. When the green LED (also known as Rx OBD) flashes it indicates that there’s data transfer from the ECU to the interface. It also flashes when data are transmitted from the interface to the computer device.

Are There Drawbacks To Using ELM327?

ELM327 interfaces are generally cost-effective and easy to use

ELM327 interfaces are cost-effective but they don’t always make the ideal choice.
———

ELM327 interfaces are generally cost-effective and easy to use. As a matter of fact they give fully-fledged scan tools a serious run for their money what with their ability to display handy data like codes, PIDs, live sensor data etc.

However, ELM327 interfaces don’t always make the ideal choice. For example, they must be paired with a mobile device or PC to work. If you would rather have a stand-alone scan tool then ELM327-based tools won’t be your favorite.

Besides, they only work with OBD2 vehicles. That locks out all car owners, enthusiasts and technicians who own or frequently work on OBD1-compliant cars.

FAQs About ELM327

  • How do I pair my ELM327?

Start by plugging the ELM327 adapter to your car’s OBD2 port. Turn the ignition on without starting the engine. Go to your phone or tablet and turn Bluetooth or Wi-Fi on (depending on which of those the ELM327 interface uses). Search for the adapter and connect with your phone to pair. Note that the name of the adapter depends on its make and model.

  • How do I get ELM327 to work?

Make sure your car’s ignition is on. Pair the scanner with your computing device that has a diagnostic app/software. It will automatically communicate with the ECU and display diagnostic data via the app/software.

  • Can I upgrade my ELM327 version?

No, you cannot. If you want a newer version you have to buy a new ELM327 interface.

  • My ELM327 adapter’s power light keeps flashing and it won’t connect with my phone. What do I do?

The interface is defective. Return for replacement or buy a new interface.

  • Where should I buy my ELM327 interface?

Check the recommendations we have given above and pick an ELM327 interface that suits your needs.

5/5 (2 Reviews)
Tim MillerFounderOBD Advisor

I knew incidentally what an OBD scanner was by searching on the Internet. Now I have over 10 years of experience in car repair and using OBD scanners. With what I know, I think I should share with everyone. That’s the reason I created this blog.

Web: https://www.obdadvisor.comEmail: [email protected]
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