Reading Your Volvo Odometer with an ELM327 OBDII Scanner

For Volvo owners of models like the 850 and V70 from the mid to late 90s, accessing vehicle data can sometimes feel like navigating a digital maze. However, with the right tools and knowledge, you can unlock valuable information, including your car’s mileage, using a simple and affordable ELM327 OBDII scanner. This guide will walk you through the process of reading your Volvo’s odometer using an ELM327 scanner and a user-friendly Android application.

Understanding how to retrieve your Volvo’s mileage is beneficial for vehicle maintenance, pre-purchase inspections, and verifying odometer readings. While modern cars offer straightforward digital odometers, older models require a slightly different approach. This is where the ELM327 scanner comes in handy, acting as a bridge to communicate with your Volvo’s engine control unit (ECU) and extract the data you need.

To get started, you’ll need:

• An ELM327 OBDII scanner (Bluetooth or Wi-Fi versions are readily available online)
• An Android smartphone or tablet
• The “Elm 327 Terminal” Android application (free and available on the Google Play Store)

Once you have these items, follow these steps to read your Volvo’s odometer:

1. Connect your ELM327 scanner: Plug your ELM327 scanner into the OBDII port of your Volvo. This port is typically located under the dashboard on the driver’s side.

2. Establish a connection via the app: Open the “Elm 327 Terminal” app on your Android device and connect to your ELM327 scanner via Bluetooth or Wi-Fi, depending on your scanner type.

3. Initialize communication with AT commands: In the app’s terminal, you’ll need to send a series of AT commands to properly initialize communication with your Volvo’s ECU. Enter the following commands one by one, pressing “Send” after each:

   • ATZ (Resets the ELM327)
   • ATL1 (Turns on linefeeds)
   • ATE1 (Turns on echo)
   • ATH1 (Turns on headers)
   • ATSP 3A or ATSP 3 or ATSP A3 (Set protocol to ISO 9141-2. Try these if connection issues arise. Usually needed only on first connection or after connecting to a non-ISO 9141-2 vehicle)
   • ATAL (Allows long messages)
   • ATKW0 (Sets keyword to 0)
   • ATTA 13 (Sets target address to 13)
   • ATRA 13 (Sets receive address to 13 – Crucially important to pair with ATTA 13)
   • ATIIA 51 (Sets initiator address to 51)
   • ATWM 82 51 13 A1 (Sets wake-up message)
   • ATSI (Optional – Initiates session. Can be omitted if desired)
   • ATSH 83 51 13 (Sets header to 83 51 13 – Use this for 1998 and possibly later models)
   • B903 (Request odometer reading)

4. Interpret the response: After sending the B903 command, the ELM327 scanner will receive a response from your Volvo. Look for a line that starts with F9 03 followed by hexadecimal values, for example: F9 03 xx yy .... The xx yy part contains the odometer data.

5. Decode the mileage: To convert the hexadecimal odometer data into a readable mileage value, you have two main options:

   • Manual Conversion: Reverse the order of the two hexadecimal pairs (yy xx). Then, convert each hexadecimal digit to its decimal equivalent and perform the following calculation: ((yy * 16^0) + (xx * 16^2)) * 4096 * 256 * 16 * 10. This manual method is complex and prone to errors.

   • Online Interpreter: The simplest and most accurate method is to use an online KWPD3B0 interpreter tool. Navigate to a website like jonesrh.info/kwpd3b0_interpreter.html, find the “Paste Volvo…communication here” box, and paste the entire line containing the F9 03 xx yy response. Click “Interpret,” and the tool will automatically decode and display your Volvo’s mileage.

6. Verify Reading Accuracy: To ensure the reading is accurate, take an initial reading, drive a known distance (preferably over 30 miles or kilometers), and take a second reading. Decode both readings and subtract the first from the second. The difference should closely match the distance you drove. Remember that the reading is often in kilometers for metric countries.

By following these steps, you can effectively use an ELM327 OBDII scanner and a readily available Android app to read your Volvo’s odometer. This process provides a valuable tool for Volvo owners to understand their vehicle’s data and maintain it effectively. Remember to always consult your vehicle’s service manual and exercise caution when working with automotive diagnostic tools.