CLK 320CDI Cut Out

[ellmo]

Hi all,

have been chasing this issue for a little while...

Driving along at low speeds or at stand still the car will cut out, all lights flash up then the car dies... no stutter or any gave away..
Starts straight up always hot or cold.

Cam and crank sensors replaced with merc ones, MAF cleaned.

No faults stored .....

would just love to solve this one.

 

[MarkPortugal]

I've had something similar; no lights flash, the car just turns off while driving. I quickly turn the key off then on again and it works normally.
Like you, no fault codes.
I was told to change the crank position sensor and MAF; made no sense to me but I did it anyway.
The problem seemed to get worse lately, happened twice within 15 minutes.

I decided it has to be the EIS or ECU; someone advertised a set ECU, EIS, steering lock, and 2 keys for the cost of a spare key, so I bought it.
So far, it's working flawlessly. I only drove about 100 miles so far though.

A bad connection on any of the above units would do it too.
The old ecu showed a fault code for the o2 sensor just before I took it out.
The new ECU seems to think the o2 sensor is a fine upstanding citizen of Mercedes.

 

[ellmo]

oh dear, sounds a pain.
any way of diagnosing it on the car?

 

[MarkPortugal]

Actually, the work wasn't too difficult. But you need to find the ecu set from an essentially identical car [engine and gearbox].
Most scrapyards don't know to keep the three parts [+key] as a set.

Other than that, you could try unplugging it all and then plugging it in again. There are many plugs on the ECU, 1 on the steering lock, and 2 on the keyswitch. A bad connection somewhere could be the problem; and it costs nothing to try.

 

[ellmo]

looks like il keep and eye out but it seems to ahve got worse over the last few days adn has been cutting out more and more..... not sure if this is expected from the unit or not

 

[MarkPortugal]

Is it the same as mine?
Just switches off, instruments all switch off, as if you'd turned off the key?
Be careful, if it happens while overtaking on a secondary road bad things could result.

 

[ellmo]

almost the same, sometimes it will allow position 1/2 on the key but wont crank
never has it cut out at anything above 20mph, most of the time its very very slow speeds....
spoke to a merc indy and they recon it does not sound like a EIS..... gets me this car

 

[MarkPortugal]

I drove again today, still working ok, no cutout with new EIS + ECU.
It really has to be one or the other I think.
I'm a newby with Mercedes, but I have good instincts for this sort of thing.
If it does cut out again, I'll post it here; I don't drive much, especially now. But when I do drive, I'll be using the Mercedes for the next month just as testing for this.
Otherwise, I drive my miserly diesel car.

 

[ellmo]

ok mate, il keep going and wait for an update