James M

So this was the story on Wednesday. I drove my car around all morning running errands and when I got into it again by lunchtime I got 'ESP Malfunction - visit workshop'. The starter motor fired and the engine turned, but would not start. I checked the fuses in the engine bay and all checked out fine. I disconnected the trunk battery for 20 minutes, then reconnected it. Same message, same problem. I then got the car towed to my indy mechanic and he called the next day to ask what the problem was because he could not find anything wrong?
The car started and drove normally and diagnostics showed no problems, not even a CPS failure? He even drove it hard to see if it was a temperature problem, but no problems surfaced. I have had an ECU problem before this when I removed my secondary air injection pump and did not replace it (useless piece of crap). We could not access the menu to 'switch it off' and stop my car throwing a permanent CEL because it was missing. This problem was never resolved and the CEL was still on when my car died on Wednesday. Any ideas or is it worth leaving my car so my mechanic can go through all the wiring to try and find the problem, which is expensive?

C32owner

It must have thrown a code? Even if it didn't again, aren't the codes stored until cleared?

Denroll

Did he scan it? What other codes popped?

shardul

iTrader: (1)

Replace the CPS with a OEM MB part and check the fuel pressure.

James M

The only code thrown was the throttle position sensor which was out because I never reset it after disconnecting the battery and then reconnecting it again. My mechanic reset it correctly and it runs perfectly without any other codes, apart from the secondary air injection pump which was removed and never replaced - my car won't allow us to 'switch it off', because it is not an option on my ECU menu. The CEL is off again, but I still can't understand what caused the original 'ESP Malfunction'? Hope this makes sense.

shardul

iTrader: (1)

most of the electronic components in the drive train are inter-related. Fault in one will trigger a fault in the other.

James M

This is suspect number 2 on my list - fuel pressure. When the engine turned it felt like it was fuel starved because I would get intermittent firing and then it felt like the engine ran out of gas the way it died.

shardul

iTrader: (1)

FP should be 80 psi at idle

MindBend

Is there a convenient location for adding a fuel-pressure sender? Never really studied it.

shardul

iTrader: (1)

Front of the fuel rail

MindBend

Is there an existing OE fitting?

shardul

iTrader: (1)

Yes

James M

Thank you kind sir. Will do both of your recommendations on Monday and keep you posted.

£ C43 £ AMG £

Check fuel pump relay also


GL

James M

Checked out everything again 1 week later and diagnostics shows zero problems? I was advised not to waste my money replacing the CPS, because when they do malfunction they really bomb out in a big way.
I have decided to stick with my motto ' If it ain't broke, don't fix it'. Hopefully I won't be posting another thread in a weeks time with a dead car in my driveway.

James M

Bought a spare CPS yesterday, just in case. At $45.00 it doesn't hurt.