ELM327: All You Need To Know Before Buying One

The EM327 is a microcontroller programmed to translate the On-Board Diagnostics (OBD) interface that you can find in most cars. ELM Electronics created the most recent and favorite of the PIC family of microcontrollers.

The ELM327 is the bridge between the OBD and the interface on your device that allows you to read your car’s system.

The parts of the ELM327 include:

1. The chip that serves as the brain of the device. This chip is either created by ELM327 or is a copy of that chip.

2. Electrical Voltage adaptors that differentiate between the various systems in the car.

3. Voltage adaptors for the PC that convert the info from the car into a form that fits your device.

ELM327 Interface

The ELM327 is the chip needed for your phones or PCs to communicate with your car. The ELM327 interface is the adaptor with the ELM327 chip inside it that allows you to read those communications. It acts as a link between your car’s onboard computer (ECU) and your device.

The OBD system in your car provides valuable information that helps you or your mechanic make needed repairs and perform standard maintenance to keep a vehicle performing.  And the ELM327 interface offers you the access you need so you can interpret that information.

Functions of the ELM327

Features of the ELM327 include:

Reading Diagnostic Trouble Codes- This includes both generic codes and manufacturer specific codes. The ELM327 is bi-directional, meaning it reads your car’s OBD and communicates with it.

The interface allows you to read the definition of each code and decide whether you can fix the problem yourself or if you need to take it to a mechanic. And your ELM327 can clear codes, so lights on dashboard turn off when issues are fixed.

Reading Diagnostic Data- The ELM327 goes a step further from just reading and clearing codes. It allows you to follow PIDs (Performance Indicators) and emissions data so you can manage your car even before those trouble codes appear.

The PID data appears in graphical form and gives you a clear picture of whether your car is performing correctly. And emissions data helps you determine if your vehicle can pass emissions testing.

Tracking Live Data- The ELM327 follows data in real-time to help you understand things like your car’s engine performance or the fuel economy.

It records live data for over 60 different measures including (but not limited to):

Average Trip Speed, Barometer, CO2 Emissions, RPM’s, Fuel Pressure, Speed, Torque, Trip Average Miles Per Gallon, Trip Distance, and many more.

Manages your Data- Data from your car logs onto your device and can be organized into reports. And those reports can be shared with others who have better knowledge than you do.

Protocols Supported by ELM327

The ELM327 is a significant improvement over previous models because those models only supported specific protocols. The ELM327, however, is compatible with protocols for almost all OBD2 model cars made after 1996.

Protocols supported by ELM327 are:

•    SAE-J1850 VPW (at 10.4 kbit/s) or PWM (at 41.6 kbit/s)

•    SAE-J1939 (either 250kbit/s or 500kbit/s)

•    ISO 9141-2 (5 baud init at 10.4 kbit/s)

•    ISO 14230-4 KWP (either 5 baud init and fast init, 10.4 kbit/s)

•    ISO 15765-4 CAN (either 11 bit ID or 29 bit ID, 500 kbit/s or 250 kbit/s )

The Best ELM327 Adapters:

Bluetooth

ELM327 Mini- The device checks parameters in real-time along with reading and clearing codes. But it does not work with Apple products.

Kitbest Bluetooth OBD2 Scanner – The Kibest monitors live sensor data and clear check engine codes. But it also is not compatible with Apple products.

Vgate iCar Pro- Depending on the power of your ELM327 app, the Vgate can run an emission test for you to see if you can pass before you take your car over to the testing location. It also works with Apple products.

Wifi

Kobra OBD2 Scanner & WiFi Car Code Reader-The Kitbest offers real-time data, works with most any car after 1996, and reads most major protocols. But the Kobra works with IOS and Android only.

Wieppo ELM327 Wifi Adapter- The Wieppo works with all devices.  It also offers real-time data and includes the library with 3000 code definitions. But the Wieppo doesn’t work diesel or hybrid cars.

Wsiiroon ELM327 Wifi Adapter- The Wsiiroom also works with all devices and reads fuel efficiency data as well. But the Wsiiroon will only clear your check engine light (so no airbag, transmission codes, etc.).

USB

ELM327 USB Adapter- This model USB adapter features great transfer speeds of 500 kbit/s. It also includes advanced diagnostics, component activation, and service reset.

ELM327 Apps

ELM327 apps are available for both iPhone and Android. These apps check and clear codes, monitor dashboard information, and talk directly to your car from your phone.

For the iPhone

Car Scanner ELM OBD2- The Car Scanner comes equipped with an extensive library of code definitions to help you clear most any check engine code. The app also features diagnostic functions, a car performance tracker, and a trip guide.

 This one is free and updates frequently, but it doesn’t include all the advanced features other brands might.

The OBD Auto Doctor is one of the best apps for planning trips. It alerts drivers with quick fuel efficiency data. A top gathering and reporting app, the Auto Doctor, is compatible with email.

The Auto Doctor reads and clears ECU codes and resets the check engine light. It also scans your emission status and pulls up live data from multiple parts of your car.

The Carista OBD2- The Carista costs more than most but is the best choice for customization. And it not only reads and clears trouble codes for your engines. The Carista also clears codes for the SRS and ABS systems.

And the Carista has a premium app that monitors tire pressure, retracts the parking brake if it gets stuck, and can perform a system reset.

For Android

Torque Pro- The Torque Pro alerts you of problems in your car thoroughly before they happen. Along with clearing engine codes, it monitors sensors and lets you know if your vehicle will pass emissions tests.

Torque Pro features a built-in dynamometer that measures torque and RPM’s. It also measures your car’s efficiency and fuel economy.

OBD Fusion- The OBD Fusion reads and clears codes, keeps up with your fuel economy, and displays a large number of gauges and graphs (including RPM, engine temp, speed, etc.), so you can see how your car is performing in real time.

The OBD Fusion supports more than 150 PID’s if you can manage the way it drains your battery.

Dash Command- The Dash Command has most all the features the Fusion has along with allowing you to check your emission status.

And Dash Command shows quick results if you have a newer model phone.

ELM327 Software for PC

ELM327 software takes the data from your car and puts it right on your desktop or laptop.

For Windows

FORScan- The FORScan works for all versions of Windows going all the way back to Windows 2000. It works for reading diagnostic codes and module sensors.

It runs diagnostic tests as well, but don’t get the Lite version if you want diagnostic testing. The FORScan reads both generic and manufacturer specific codes. It also displays data in text form.

However, FORScan’s are not compatible with all car models.

EngineCheck works for all gas-powered cars made after 2001 and diesel cars made after 2004. 

EngineCheck works almost exclusively with the check engine light. It does include a handful other features, including live sensor data and fuel system status.

Freediag works exclusively with CLI (Command Line Interface). It reads and clears the Check Engine Light and is supported by five protocols (ISO 9141, ISO 9141-2, ISO 14230, SAE J1850 (PWM and VPW), SAE J2818/KWP1281/VAG), and the Mercedes Gearbox Protocol.

For Mac iOS

goSerial- The terminal interface reads and clears the Check Engine Light and emission-related codes. It keeps multiple connections open at once using a simple serial connection. And it’s completely free.

OBD GPS Logger- The GPS Logger compares code readings to the location of your car and downloads it on your computer. It allows you to track how efficiently your car is running and make a note of the place where your vehicle started experiencing problems.

Also, the GPS Logger runs on OSX and Linux systems.

ELM327 Adapters: Which One is Best for You?

There are three fundamental ways to connect your ELM327 to your device: Bluetooth, Wifi, or USB cable.

ELM327 Bluetooth Adapters

Since all modern phones (and many modern cars) have Bluetooth capabilities, Bluetooth works almost anywhere. You aren’t dependent on a Wifi network if you have a Bluetooth adapter. You can also buy these adapters at a very affordable price.

But Bluetooth adapters transfer data at a slower pace than wifi. You also have to be within proximity of the car to get it to work. That means you can’t multitask while using this ELM327 adapter. If you use a Bluetooth adapter, your vehicle will have to get all your attention.

ELM327 Wifi Adapters

Now keep in mind, most ELM327 wifi adapters aren’t connecting to a local network. They create a network to communicate with your car.

Transfers happen quicker with a wifi adapter than they do with a Bluetooth one. The wifi adapter reaches a greater range than the Bluetooth adapter will. That allows you to shop for the new parts you need to fix the problem your ELM327 is finding.

And many computers don’t even have Bluetooth, but all computers have wifi, so the ELM327 wifi adapter offers greater variety in the kinds of devices its compatible with.

But most wifi adapters cost more. And you must remember your password even if you set up an auto login. It can be challenging to get back into your ELM327 if your device logs you out, and you don’t have your password on hand.

ELM327 USB Adapters

USB adapters are the true wildcard in this debate.

If your desktop or laptop is the device you rely on for car data, then the USB adapter might be your best option. All computers have USB ports, so you know it will be compatible. And many USB adapters produce high transfer speeds.

Range and mobility are the most substantial concerns with the USB adapters. Some with significant range can read your car while you sit in another room. But others will require you to take your laptop into the garage because of a lack of variety.

And most phones don’t support a USB connection, so that limits the devices you can use your USB adapter with.

FAQs about ELM327

1. How do I pair my ELM327?

Plug in your scanner into your car’s OBD II diagnostic port. Turn your ignition to the 2nd turn, so the engine stays off. Then, activate the Bluetooth on your device and scan for your device. When the name of your device pops up, click on it to pair.

2. How do I get ELM327 to work?

Plug in your scanner and turn on the ignition (the 2nd turn right before the engine is powered). On your device, go to settings, go to wifi, then connect with the Wifi signal associated with your ELM327 (examples for names include WIFI ELM327, WiFiOBD, etc.)

After you’ve connected your device to the ELM327’s network, open your OBD app. Go to the app’s settings and set it to look for Wifi (it may already do this by default).

3. How do I connect my ELM327 to my iPhone?

For Bluetooth, launch the app and go to settings.  Select the connection, then select connection type: Bluetooth. The search should produce your device. If it does not, click “update” to refresh the system.

For wifi, plug in your scanner and turn on the ignition (the 2nd turn right before the engine is powered). On your device, go to settings, go to wifi, then connect with the Wifi signal associated with your ELM327 (examples for names include WIFI ELM327, WiFiOBD, etc.)

After you’ve connected your device to the ELM327’s network, open your OBD app. Go to the app’s settings and set it to look for Wifi (it may already do this by default).

4. What are the risks of a Clone or a Pirate ELM327?

The ELM327 microcontroller code wasn’t copyrighted so anyone can produce a copy of it. The clones and pirates are cheaper and feature similar abilities. But they are often buggy and don’t update (even if they say they have).

For example, the first ELM327 put out by ELM Electronics marketed as version 1.0. Many pirate versions cloned the 1.0 software into their devices. But then, they traded “updates” (1.1. 1.2, etc.) that were not actual updates, just the 1.0 software pretending to be an update.

5. How do I spot and ELM327 Clone?

Check the version of ELM327 being advertised. An ELM327 with an interface of 1.5 is not a real version because ELM never realized this version.

And there are apps (such as Android’s “ELM327 Identifier”) that identify what version of the ELM327 chip is present so you can determine if the product is lying about how up-to-date it is.

Read more: Best OBD2 Scanner: Complete Buying Guide and Review 2021