Fivehunnit

So, today while accelerating, suddenly the car started to lurch and sort of try and stall, I got a warning like (ESP defective, visit workshop!) and the car cut out when I came to a stop.
It then started normally but the engine light is on, it runs with a slight hesitation upon accelleration now, but the malfunction warning hasn't happened again, any ideas?

Rudeney

You need to check codes. A cheap generic OBDII scanner costs about $30 and can pull ECU codes. Some auto parts stores do it for free. Note that this won't scan the codes from the ABS/ESP system - you'll need an advanced scanner like Star Diagnosis for that. Generally and ABS/ESP fault in and of itself won't trigger an MIL, but if it fails causing the car to stop unexpectedly, it can cause other temporary faults, like a misfire, that do trigger an MIL.

Fivehunnit

Thanks, will get it plugged in at a local Indy, update, this morning I came to rest at a junction and suddenly it accellerated something fierce, had I not been on the ball, I would've ended up putting a big mercedes imprint in someone's door.
The engine check light is still on, still split second hesitation when the throttle is pressed, I can get it to the floor and back with no increase in revs, but under normal driving it's not totally unmanageable (for now).
Is it likely to be the throttle position sensor? And if so, which one? Does it have one on the pedal and one/several on the throttle body? Is there any way of testing such as if there is lag in the pedal but the throttle responds ok when operated by hand at the body? (Can't find that as yet).

Rudeney

The accelerator pedal itself is electronic and sends a signal to the ECU which in turn controls the throttle, which feeds back a signal from its position sensor to the ECU. There is a resync procedure (search the form for TCU or ECU rest) that might help, but I suspect you will have a code indicating either a bad accelerator or bad throttle position sensor.

Fivehunnit

Thanks yes tried that and no difference that I noticed, engine light still on etc, is there only the pedal that sends signals to the ECU/throttle, or is there others on the throttle body that recieve from the ECU?
Also, are the pedals all the same on the W209? Eg could I get a 320 pedal and it would work? Even the diesel? They seem to list them under just the chassis number and year on eBay with no engine size/type

Rudeney

The ECU actually controls the throttle based primarily on input from the accelerator pedal, but also other sensors do come into play. Before swapping parts, get a proper diagnosis. Also, the accelerator pedal has different part numbers based on VIN. If you do get ready to buy one, let's check EPC for the right one for your VIN.

Also, I noticed that you say you have a 2002 CLK500 - there is no such thing. MY2002 was still the W208 chassis, which was the CLK430. You car is likely a MY2003, with a plate or registration year of 2002. I know this can be confusing, especially outside the USA where "model year" is less important. However, like most makes, MBZ begins building and selling the new model year vehicles the year prior.

Fivehunnit

Had it plugged in today and the results "Pedal value sensor short circuit "
Is that the sensor on the pedal itself or on the throttle body?

It's a 52 reg (in the UK that means late 2002 or more, between September of one year and April of the next I think),so yes, I guess I should refer to it as a "52" but thought it may confuse people that don't know that system. It's just after the time the 208 was discontinued. it's definitely the W209

dnpushkin

Hello sir,
I had a similiar problem with my 2004 CLK 320,
My EBS/SOS/Visit Workshop came one after going down the highway and after a a few days the car wouldn't start.
I would highly suggest checking your alternator and belt first. This was the cause for my car, and of course make sure it is in all the way.
Go to an advance auto parts or autozone, or anywhere they will check a battery starter and alternator free. My diagnostic when I initially ran it came up under a multiple of codes, because of course the model links electrical issues to a few things.
My suggestion is to check the alternator and make sure none of the diodes are failing.

Fivehunnit

Update, it's been left with an indy garage since yesterday, the fault codes are still there for MAF and TPS despite me replacing them, they also tested them and say they're in working order, and that they're now working on the wiring loom to see if it's that, and if not, the only remaining thing is the ECU :/

Fivehunnit

Wiring replaced and no different, now the ECU has to be sent out for repair, can't even begin to imagine how much all this will cost, it's getting sold as soon as I get it back, first and very last MB

Benz2002

I have a 2008 E350 4matic. my ABS/ESP light comes on too. Mine comes on when I cut the wheel sharp to the left. If I shut the car off for about 10 mins. it resets (no light and steering is normal). My service shop says to bring the car in when the light is on so they can scan. However so far its been inconvenient to do so at the times the light comes on.
Does anyone have any suggestion as to what I could check on my own?

Fivehunnit

I've heard a faulty wheel speed sensor can cause symptoms like that when the symptoms are linked to steering, wait for others to come in first.

Rudeney

It could also be a faulty steering angle sensor (behind the steering wheel, part of the clockspring assembly). Getting codes pulled form the ESP system is the certain way to know. Generic OBDII scanners won't do this, so it's likely you'll need a visit to the dealer or an indy with proper equipment.

Benz2002

Thanks guys, I will take your advice and bring it to the shop.