Hello, I have a citroen vehicle that uses CAN protocol to communicate with the engine, which is already communicated with it, but ecu of a room (BSI) uses UDS protocol, and I can not see frames, is like CAN but slower?
it may be that UDS uses the same slow CAN protocol, but in pinout obd 8 pin = CAN H and pin 9 = CAN L low speed?
UDS is a protocol on top of CAN. It’s like the onion style layers of TCP/IP. That’s TCP over IP which itself might be going over DSL, ethernet, or QAM cable, etc. UDS messages are CAN frames with a specific format.
So, if you can read CAN messages you can read UDS messages. If you aren’t seeing any then there are a few reasons why 1. You might be using the wrong speed 2. you might have the wrong pins 3. You might have connected the wires backward. So, yes, you’ll have to check your pins and your speed but any CAN device is going to be able to read UDS messages. Note that not all CAN buses go to the OBDII port. You might need to tap wires under the dash or in the engine compartment.