iPhone and iPad OBD-II Apps

iPhone, iPad, and iPod Apps

There are a few OBD-ii Apps on the app store. Here is my recommendation of the apps that are available.



A great application in the App store that will work with WiFi OBD-II adapters is called EngineLink made by a company K Solution. The app comes in both an iPhone/iPod version as well as a version specifically for the iPad. I own both and I can say that this app works very well and is a great value at $6. It allows for custom PID’s (Parameter ID’s) that allow for monitoring of advanced engine parameters, a fully customizable GUI (Graphical User Interface), multiple ECU (Engine Control Unit) support, and multi-page display.

Getting Started

Once you install the app you will be greeted with a screen that tells you to purchase a ELM 327 OBD-II WiFi adapter. There are arrows on either side of the screen that will change the pages and these pages serve as directions to get your device connected to your iPhone. Once your adapter is plugged into your OBD-II port go to your iPhone’s settings and choose Wi-Fi. Connect to the Wi-Fi network that your OBD-II adapter is broadcasting. (mine is CLKDevices). Configure the static IP address (mine was exactly like the directions in the App as well. The IP I use is with a subnet mask of Now it is time to head back to the EngineLink app and enter in the IP address of your adapter. (mine again uses the numbers displayed in the directions with a port number of 35000). Once you get the correct IP and port number set tap ‘Connect’ and wait for the status to change from “OFFLINE” to “ONLINE”.

Checking Engine Codes

Read Engine CodesOnce you get your adapter added in the EngineLink app you can use the app to read the codes that are stored in you cars computer. Make sure that your adapter is plugged firmly into your OBD-II port and turn the key to your car to the ‘Accessory’ or ‘Run’ position. This is the position right before the car will actually start, and the position that the key is in while the engine is running. Once you do this you should be able to connect your iPhone to the adapters WiFi network and connect to the app. Head over to the page shown here on the left and tap ‘Read Trouble Codes’. If your vehicle has any codes stored they will be displayed here in the list. Make sure you write them down and head over to our page on engine codes to find out what they mean. Once you have them all written down you can tap ‘Clear Trouble Codes’ to turn the light off.

Configuring the App for Real-Time Data Display

My EngineLink SetupNow we are ready to set up the app to monitor just about any vehicle parameter you can think of. I have a 2009 Toyota Prius that I hook this up to a lot so my favorites are shown here to the right. To add a value tap and hold on one of the empty screens. A menu will display to allow you to choose the type of display you would like the value to be displayed in. The types include ‘Small Dial’, ‘Big Dial’, ‘Small Bar’, ‘Big Bar’, ‘Small Plot’, ‘Big Plot’, ‘Small Digital’, ‘Big Digital’, ‘Small OnOff’, ‘Big OnOff’, and ‘Background Color’. In my setup the ‘HV SOC’ (High Voltage State of Charge – or hybrid battery %) is set up as a ‘Big Plot’. ‘HV Current’ (High Voltage Current In/Out) is set up as a ‘Big Bar’. ‘ICE Rev’ (Internal Combustion Engine RPM) is a ‘Small OnOff’, ‘Coolant Temp’, ‘Brake Pad’, and ‘Regen Brake’ are all ‘Small Digital’. I have also changed the background color to black but you can choose any combination of PID’s, gauges, and colors that you would like! Once you get the PID’s that you would like displayed on your screen drive around a bit and you will be able to see the information from your car in Real-Time!

Note: When adding custom values you will be presented with a list of values that can be chosen. If your car is supplying data for the values the picture of an engine with ‘PID’ written in it will be green. If the icon is gray your vehicle is not providing information for that PID.

Adding Custom PID’s

The easiest way to add a custom PID is to first choose the style of display that you would like the value to be. I am going add instantaneous MPG so I am going to choose ‘Big Digital’. On the ‘Custom PID’s’ page tap ‘Edit’ in the top corner. On the left side now tap the ‘+’ button to add a new PID. For the MPG PID we will need to set values as below. Then choose done.

Header: 0AddCustomPID
PID: 010D
Formula: mpg
Min: 0
Max: 100
Description: Instantaneous MPG
Unit: Mile/Gal

As you can see in the screenshot above the PID is now in the list and can be chosen to be displayed on the page!

Changing PID Definition Files (*.csv format)

Another cool feature that EngineLink supports is the capability for custom definition files. This allows you to customize the PID’s you would like to monitor on your computer in a .CSV file and change between them within the app. A great example to how this is helpful is that most (if not all) of the PID’s that my 2009 Prius supports aren’t supported by my 2003 Explorer. By changing from one definition file to another I EngineLink Custom Definition Pageam able to keep the modifications that I make to each when switching from vehicle to vehicle. By default the ‘Standard_PID_US.csv’ definition file is selected so if you happen to have a Prius like I do most of the hybrid PID’s won’t be availble. To switch between definition files go into the ‘Custom PID’s’ screen by tapping and holding on one of the empty pages. Choose ‘Edit’ then ‘Load PIDs’. You will be presented with the screen you see above. Since my Prius is a 3rd generation (2003-2009) I chose ‘Prius_Gen2_US.csv’. Then choose ‘Done’ and choose the PID you would like displayed. That’s it! Now you have switched definition files!

If you would like to modify existing definition files you can access them through iTunes sharing. In iTunes on your computer choose your device and go to the Apps section. At the bottom under ‘File Sharing’ you will see EngineLink listed. Click on it and you will see a list of .CSV files. Click on the one you want and drag it to your desktop. You can now edit this .CSV with any text editing program or programs like Excel. Once you make your modifications you can drop the file back onto your device in the same way. I have posted a link to the .CSV file that I use for my Prius. All I have done is add the ‘Coolant Temp’ custom PID, Instantaneous and Average MPG. Feel free to use it and share it with your friends!

Developer/App Support

One of the important things that is required to have a great app on the iTunes App Store is great support and EngineLink doesn’t fail there! I contacted K Solution and asked that they include the ‘On/Off’ and ‘Digital’ custom displays. I also requested that they include a way to add custom displays for the instantaneous and average MPG. I was very surprised to see all of my requests included in future updates and even more surprised to get the updates very quickly. If you have any questions about the app you can post below or contact K Solution directly.

Recommended WiFi OBD-II Scanners

My WiFi AdapterOne of the important things about using an OBD-II smartphone app is making sure that you buy a WiFi scan tool that is going to work well with your phone. I have nothing but good things to say about the scanner here shown on the right. It has a very fast update cycle for always up to date engine data and is easy to connect to your iPhone or iPad and configure within the EngineLink App. And at $35 it is a great buy! Click on the picture to be taken to Amazon and give it a try. Don’t be shy to post your experiences in the comments below! There are many others that are willing to help.

Here is EngineLink‘s official YouTube video!