Is there a "Howto" to help diagnosing CPS faults?

[PJayUK]

My ML320 has without doubt been one of the most trouble free cars I have ever owned, but it has recently developed an issue. I am pretty sure its the CPS however as hard as I have looked on this site and others, there doesn't seem to be a definitive list of the symptoms that could confirm if the CPS is the culprit.

Basically the car will start no problems from cold but once it gets to operating temperature hesitates when overtaking. It also stalls randomly at lights etc but also when placed under load eg. climbing a hill. The issue is becoming more frequent and I am 99% sure its the CPS but would appreciate any thoughts or advice etc before I point the finger!

Its looks like a pretty easy DIY job if so and as its nice outside I fancy having a crack at it myself. So any further tips on this job would also be gratefully accepted!

Cheers

 

[grober]

CPS failure is characterised by the engine cutting out once the engine block heats up. Waiting for the block to cool down then restores function. Eventually it fails permanently and the engine won't restart cold or hot. Not sure if your symptoms as described fit the bill for that. Sounds more like a MAF or EGR problem??

 

[PJayUK]

Ok thanks, I know that I need to get the codes read I was just hoping that it could be an easier diagnosis based on the symptoms. I would expect the car to run a bit rougher if it was MAF I dont know what symptoms of EGR blockage or failure are...

It had a new MAF a couple of years ago but I guess this could have gone again!

 

[BlackC55]

Codes rarely come up for CPS issues on a 112 V6 engine. It could be somthing else causing theis fault quite easily. An air leak for example.

 

[PJayUK]

Probably need to bring it in (Olly you have fixed it for me before, in fact you replaced the MAF for me when it was serviced.) I was just hoping it was something simple!

Probably have a little think on this, as its going to be a while before I have the time to get the car looked at.