Logging OBD2 data

In this section we outline how to log OBD2 data with your CLX000.

Configure your device

First you configure your device to transmit OBD2 ‘request messages’:

  1. In the ‘CAN-bus’ section, disable silent mode and set the bit-rate to 500K (for cars)
  2. In the ‘Transmit list’ section, click ‘OBD’ to add up to 20 PIDs to be requested by the device[1]
  3. Optionally adjust the request period/delay or add custom OBD2 PID requests
  4. Export the configuration file to your device SD card

Record data from your car

  1. Connect the CLX000 to the OBD2 connector in your car via the DB9-OBD2 adapter[2]
  2. Verify that the device turns on and logs data (see the LED section of the CLX000 Docs)
  3. Disconnect the device and review the TXT log file via a text editor
  4. If your car responds[3] you should see CAN frames with ID 7E8[4] in your data
  5. Once confirmed, you can optionally optimize your Configuration File[5]

Analyze & plot your OBD2 data

The CANvas conversion intro details how you can convert raw data from the CLX000 into human-readable form - and e.g. export it as CSV. You can decode raw OBD2 data with the built-in OBD2 database in CANvas (see the black database icon) in the ‘Create/load database’ section.

OBD2 data logger

OBD2 & battery consumption

The CLX000 consumes <1W, which is not an issue for your car battery in practical use cases. In most cases, the device also turns off with your car (or 10-20 min after). However, if this is not the case and you’re requesting OBD2 data, the device may “wake up” the car sensors.

In such scenarios, there are a couple of options:

  1. You can simply disconnect the device between trips
  2. You can re-wire your vehicle’s OBD2 connector so that the power pin is linked to the ignition
  3. If your use case requires a dynamic toggling of the OBD2 requests, consider the CANedge

[1]Note that the default list in CANvas matches most of the Mode 01 PIDs, but you can manually add custom OBD2 PIDs. Further, if your vehicle uses extended IDs (e.g. for light trucks), you may need to use the request ID 18DB33F1. The responses in this case may come on 18DAF110
[2]We recommend using one of our DB9-OBD2 adapters. If using a 3rd party cable, it’s important to verify the pin-out.
[3]Note that some older cars do not support OBD2 data acquisition via CAN bus, while some newer cars block CAN access via the OBD2 connector. For cars that do support OBD2 data, the extent of coverage varies. The “supported PID” single-shot requests can help provide information on what PIDs are supported. If your car does not respond to the OBD2 requests, we recommend to test in other cars to determine if the issue is specific to the car or e.g. the Configuration File
[4]In some cases you’ll see IDs like 7E9. In this case, you may need to modify the OBD2 conversion database to use alternative CAN IDs
[5]For example, you may want to add filters to only record OBD2 responses. Also, you may want to add custom OBD2 PID requests - see our simple intro to OBD2 and the OBD2 PID Wikipedia page for details on this