CSL '0401' Program Binary Disassembly Notes

[Bry5on]

So it looks like the 0x03+ message format is the same for both IDs 0x700 and 0x701

For Byte 0
bits 0-2: cylinder ID (0x700 only reports 001, 010, 011 and 0x700 only reports 100, 101, 110 as expected)
bit 3: no function (for MSS54/HP, this is probably used in the V8 M5 though to ID cylinder 8)
bit 4: knock detected (1 for knock detected)
bit 5: no function identified yet. Could be related to bit 4 with a type of knock detection state.
bits 6 and 7: some sort of evaluation state. So far I only see values of 11 and 00, where the transition happens after cranking the engine. Probably ‘engine running’ or something similar.

I have a datalog recorded that I’ll need to parse tonight to evaluate the other Bytes.

I’ve also flashed a new file to my car with some extra ignition advance to see if I can trip some knock.

[karter16]

Awesome thanks for that - I haven't had a chance to go through the log you sent in detail yet, but what you've posted there makes sense. The frame is exactly the same for either bank, just bank 1 sent on 0x700 and bank 2 on 0x701.

Will be super interesting to see what you get if you can cause some knock. As I mentioned I *think* that byte 1 is the amount of retardation being applied for the cylinder - will be interested to see what you get.

[karter16]

Came across the OBD2 readiness monitor functions today:

This function passes a pointer to obd_check_monitor(). The pointer points to an array of bytes which list the DTCs that are applicable to the monitor in question. The DTCs are evaluated against stored status and the monitor status (ready or not) is returned.

[karter16]

I've now figured out 128 of the 138 parameters specific to the CSL. You'll see that my naming conventions aren't entirely consistent, but once I've figured out the last 10 and have a complete view I can then align the naming accordingly.

[ac427]

I've now figured out 128 of the 138 parameters specific to the CSL. You'll see that my naming conventions aren't entirely consistent, but once I've figured out the last 10 and have a complete view I can then align the naming accordingly.

Excellent work mate 👍