Well, I had some spare time today to look into this further and so I got out the laptop and started coding.
I wanted to reset the coolant over temp (UEBERTEMP) alarm down to 110c so I started with that. Seemed to go ok, used NCSDummy to modify my LCM.C23, loaded the LCM trace from the car, updated it, reloaded the modified .man file - all good. Except it didn't work - when I read the LCM trace back from the car (after several ignition recycles) the overtemp alarm is still set at 125c. What the heck.
So I moved on to the speedo error fix, read the trace for the IKE (KMBI), added the Japan speed settings, then reloaded the modified .man file - and got a nasty CABD! error and the coding failed! The error was COAPI-2061 which seems related to checksums.
As we say downunder - bugger!
I re-checked everything, and reloaded to factory default trace - all OK this time, coding completed without error. IKE was fully reset, had to reset time and date, lost any stored fuel consumption values and settings on the BC etc. Also lost about 30km from my ODO, I guess caused by the IKE reset and the ODO value being replaced by that in the LCM.
Scary shite....!
All seems ok, car is working as it should, but nothing I tried to code worked. Going to give it a while to re-settle my nerves after all that! In hindsight, screwing with the two modules that hold the ODO data at the same time might be a bad idea!
So it currently seems that simply adding the Japan speedo settings resulted in a checksum problem but it may have been an error on my part. I guess maybe if someone else is game to try it, we might find out if it works on the e53 platform?
