Three digit PIDs in OBD II

Question

I'm in the process of writing a java based application to interface with a car. For hardware I'm using one of the wifi ELM 327 modules available from Amazon (this one to be precise: http://www.amazon.com/gp/product/B00FQ7O88M/ref=oh_details_o00_s00_i00). To test that it's working, I picked up the DashCommand application for my iPhone.

To get a bit of a look into the protocol used to interface with the module, I recorded the network traffic of a session (via wireshark) where I went on a drive while the DashCommand app recorded it's usual metrics (the car used for testing was a 2009 Acura TSX).

Most of the traffic initially is what I would have expected from what I've read in the documentation of both the ELM 327 and OBD II. However, once I got going, DashCommand ended up using PIDs that I can't seem to figure out. An example of what I saw would be:

...
Request: 01 0B2
Response: 01 0B2
          18 DA F1 11 03 41 0B 1B
          18 DA F1 1D 03 41 0 B 1C

          >
Request: 01 0C2
Response: 01 0C2
          18 DA F1 1D 04 41 0C 0C A0 
          18 DA F1 11 04 4 1 0C 0C A0 

          >
Request: 01 0D2
Response: 01 0D2
          18 DA F1 11 03 41 0D 00 
          18 DA F1 1D 03 41 0 D 00 

          >
Request: 01 101
Response: 01 0D2
          01 101
          18 DA F1 11 04 41 10 01 3E

          >
Request: 01 332
Response: 01 332
          18 DA F1 D1 03 41 33 62 
          18 DA F1 11 03 41 3 3 62 

          >
…

The full list of three digit PIDs I've found so far are: 031, 0B2, 0C2, 0D2, 101, 332, and 341. Each of these are sent with mode 01 as shown above.

Is there any documentation on these PIDs? Or am I misinterpreting what I'm seeing?

score 2 · Accepted Answer · answered Jul 02 '14 at 10:04

The last digit is not part of the PID.

The number after the PID represents the number of replies you're expecting. You can see that this is always a number.

For example, when you add a '1' to your normal 2-digit PID, the ELM327 will wait for exactly 1 response from an ECU. When 1 ECU has responded to the ECU, the ELM327 will directly respond that result to you. When you add a '2', it will wait for 2 repsonses.

Source: ELM327 Documentation - Go to page 32.

Three digit PIDs in OBD II

1 Answers1