Volkswagen OBD-II data retriving

[Cparu]

Hi everyone, i am new there, trying to find an end to a project, a digital gauge cluster with an arduino, an MCP2515 to read the canbus and a screen.

This is my project, it retrives data from the OBD-II port and puts it on the screen.
The project started because i’d like to know the oil temperature of my VW Polo 1.4 TDI diesel.

I can easly read “standard” SAE OBD-2 PIDs that are sent with a 7DF functional group and a byte as the request.

The problem is that very little information is returned by the car that way, because Volkswagen seems to be using a functional group (header) of 7E0 for engine data, and 3 Bytes as the requested parameter.

Here are two links about some PIDs. The two links have some PIDs in common, reerring to the same parameter and woth the same formula for “decoding”, so they seem to be reliable.

VAG PIDs

bri3d/MQBSimosLogVariables/blob/master/exportedPIDs.csv

The problem is that, when i try to send them i get no response at all, i dont know if i am doing something wrong, if the codes are wrong or i am just not reading the response, Have someone seen or did a similar project?

Here is the letest code i am using to try to read data. Output is Serial only, not using the screen.

/* CAN OBD & UDS Simple PID Request * * Currently requests PID 0x00 at a...

and here is the output i get, basically noting or i get my obd-II packet back, not sure

here i am trying to read engine rpm, the car is on and the eingine is running.

Thanks for the time to read this.

[Stonksonlygoup]

God Tier level stuff here.

[Cparu]

okay, i noticed that i had

  // Having problems?  ======================================================
  // If you are not receiving any messages, uncomment the setMode line below
  // to test the wiring between the Ardunio and the protocol controller.
  // The message that this sketch sends should be instantly received.
  // ========================================================================
  CAN0.setMode(MCP_LOOPBACK);

this activated, so the mcp was giving back the message sent. I removed this line and i get noting as a response.

[Cparu]

After disabling all filtering, i seen that

1. my message gets completely ignored
2. there is only a single message to be read on the bus.
   Is this some sort of request of autentification or what?
   
   

Edit:
It seems like that che car gateway does not want me to communicate with the car. There is a similar post on reddit that says
VW uses a proprietary “TP 2.0” or “VWTP” over the CAN bus, carrying KWP2000 frames; you may be able to find an Arduino implementation, you may not.

[jeisensc]

Great thread. I moved it to the Tech Lounge where it is more likely to get the appropriate attention.

[Cparu]

Thanks, wasnt really sure where to post it.

[Cparu]

Hi everyone, unfortunately i did no no progress.

I tryed to send UDS requests with this library : GitHub - altelch/uds: ISO 14229-1 UDS protocol implementation for Arduino that unfortunately seems to be the only available and it gives me an error, i tryed all the 2 examples provided. Have anyone done this? Do you recommend some other library that i could not find? I also have some esp82266 and esp32 available if you know something for those boards, thanks.

[edmcman]

What error are you getting from UDS?