Mk7 "Engine malfunction" & MIL light

[Johnxair]

Hi All, I've got an unsolved problem with my van (2013 built, MK7 2.2 100ps, RWD, LWB, High Roof). I'm a newby here, I've learned a lot but still need a bit more help with this.
Some months ago and immediately after a cold start, the engine malfunction warning came up about 5 seconds after engine start. Once the engine was warm and the engine stopped, it didn't reappear after a restart. However, continuing without a restart would eventually bring on the MIL light and I would be in limp home mode until the codes were cleared. The fault code was Mass Airflow Sensor reading too high. Fitting a new sensor made no difference and the MAF wiring back to the fusebox appears ok. Apart from the performance limitation of the limp mode, engine performance is fine. (No spluttering, cutting out, refusing to start etc.). I carried on like this (stop and restart 2 miles after a cold start) until the 'engine malfunction' warning no longer went away and the MIL light would soon follow. My suspicions were turning towards the EGR.

I bought the ELM327 and was for the first time able to view my PID data. I selected everything that looked EGR related and among the active looking oscilloscope traces, two didn't move! The EGR Position and EGR Error (which stayed at 100% irrespective of engine speed & throttle position). I put a new EGR on it (a Hella, not a cheap one!) and after clearing the codes of course.....it made no difference at all!

My attention has turned to a possible broken wire between the EGR connector and the PCM. However despite studying a wiring diagram I found on this forum, I'm struggling. My wire colours appear different and I haven't identified which connector on the PCM I need to investigate.

The fault codes I'm getting are:
PCM: POOBD OO-AE
OBDII: POOBD-C
RCM: UO155
PCM: POOBD OO-A7
OBDII: POOBD-P

I believe these are MAF airflow too high
and loss of communication with instrument panel cluster control module. (I've assumed the second one is insignificant)

Any advice you guys can offer would be great!
Thanks
John

[Johnxair]

I'm still struggling with this one. Can anyone tell me where to find C3 on the ECU/PCM? I assume this is 'connector 3'? I'm looking at a wiring diagram posted on this site in 2017. I need to trace my wiring and check continuity.