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04colyZQ8 wrote: ↑Wed Jan 03, 2024 3:26 pm I’m well versed in vpw now but still learning gm lan.

I’m observing a tech 2 and what to see what pid changes for clutch depressed, but there are several ones under transmission.

Are they still called mode AE pid requests?

Any literature on these pids?

Tazzi wrote: ↑Wed Jan 03, 2024 8:33 pm

04colyZQ8 wrote: ↑Wed Jan 03, 2024 3:26 pm I’m well versed in vpw now but still learning gm lan.

I’m observing a tech 2 and what to see what pid changes for clutch depressed, but there are several ones under transmission.

Are they still called mode AE pid requests?


Thanks Tazzi I love your knowledge:)

Any literature on these pids?

Live data is typically setup as DPIDs (Dynamic PIDs).

Basically theres some setup commands to tell the module which live data parameters to start broadcasting, and then the module will start spamming out the live data.

gmtech825 wrote: ↑Wed Jan 03, 2024 10:50 pm the DPID data the ecm broadcasts will be under the ID 0x5E8. the scan tool will request mode 0x2c to tell the ecm what pid to put in what buffer, and then I think mode 0xAA is the scan tool request to start the data broadcast. I can clarify more if it's needed. mode 0x22 is the request for the ecm to return the pid once, and the response ID will be 0x7E8

Tazzi wrote: ↑Fri Jan 05, 2024 2:30 pmFor reverse engineering, I actually use an OBDX Pro to simulate the 'ecu' responses to something like Tech2win, and then I change the live data values being spammed back to work out what each byte/bit corresponds to. Its a bit of a lengthy process, but, its the reverse engineering way.