Help required - 2001 W203 C180 Erratic Revs - scary

[TazCBR1100XX]

Hoping for the usual helpful (and cost saving) tips from the experts on here

My 2001 W203 C180 Classic Auto has suddenly developed a VERY scary fault. It's as if the flipping footbrake has connected itself to the accelerator. Here are the symptoms:

When driving at a steady 40mph in top gear with D selected, the engine suddenly changed down a gear or two as if I had kicked down - and that's on a fairly level road. So the revs increased dramatically without me exerting any extra pressure on the accelerator. It then seemed to take forever to change back into top gear, but it did eventually get there. When I first noticed this, I thought that perhaps the clutch was slipping a bit hence the reason why it didn't change up to top gear easily. But now I'm almost convinced it's an electrical/electronic problem. the car has done about 115000 miles and is still on the original clutch.

When on the motorway, I was slowing down to get off at a roundabout. As I slowed down, I put my foot on the footbrake, and the pigging thing started to accelerate. I thought at first that something was fouling the accelerator, but on checking it all looks pretty clear of any obstacles such as carpet etc.

Following the above mentioned scary moment, I decided to try a few things out in order to gather more information. If I do about 40mph and just hold it there, every now and again, the engine will just start revving higher and my speed increases. When it's doing this, I can slip it into neutral, and it will either rev higher for a short time, or red line before dropping down to normal revs.

I also tried coasting along in neutral (again at around 40mph) with my foot off the accelerator and covering the footbrake but not pressing on it. Again it randomly and unexpectedly starting revving like crazy.


Any ideas on what it may be, what I can check, and what I need to replace?

Are there any Independent garages anywhere near Doncaster / Lincoln / Scunthorpe that could help me out?

Thanks in anticipation.

 

[TazCBR1100XX]

Well I am surprised - I would have thought that someone would have come across this before Ah well, Mr Mercedes it is then I'll let you know the outcome :arrow: watch this space

 

[jibcl500]

At a guess I'd say the electronic throttle is on its way out.

You need some diags on the car and soon.
jib

 

[TazCBR1100XX]

At a guess I'd say the electronic throttle is on its way out.

You need some diags on the car and soon.
jib

I'd say the electronic throttle has probably gone (and shut the door behind it). Car booked in to MB Thursday - in the meantime it stays put cuz it's dangerous.

Good job I've got the motorbike to ferry my wife around while her car gets fixed

 

[TazCBR1100XX]

Oh dear - NOT the throttle body Mr Mercedes said there was a fault registered on the system, but they changed it for a new one and there was no change in the fault So it's now in their hands with a couple of techie type bods scratching their heads trying to work out why the brake pedal has become and accelerator

More news later if they find anything!

 

[TazCBR1100XX]

All sorted thanks to the exceptionally good service offered by Mercedes-Benz of Grimsby - AGAIN! I can't praise the dealership enough for sorting this out for me - and what's more, they didn't charge me a penny for the couple of hours work they put in resolving it.

The really scary bit though is that I reported the problem (and the cure) to Mercedes Benz Customer Service, and they weren't remotely interested, even though I stressed the potential for accidents should someone else suffer the same fate. My car's fine now, and that's all they are interested in. Their technical people refuse to accept that a Mercedes Benz car can accelerate under braking conditions, and Mercedes wouldn't even take up my offer of the use of my car so I could PROVE it to them.

Ah well, like they said - my car is OK, but if anyone else has this problem and someone gets killed or injured, it won't be my fault because I have tried to tell them

Anyone want to buy a 2001 C180 Classis Auto :-D

 

[TazCBR1100XX]

I just noticed - this is almost a one man thread - must go out and find some friends

 

[Blobcat]

I just noticed - this is almost a one man thread - must go out and find some friends

Strange really, not sure why you haven't had more replies perhaps the "scary" in the title kept people away...

Still the suns shinning down here so I'll be out on my CBR later

 

[TazCBR1100XX]

As it happens, I've spent the last couple of days blasting around on the XX as the sun has been shining up here too. Having said that it rained just before we got to Grimsby today so it looks like I've got some cleaning to do over the next few days The Merc hasn't moved except for when we had to do the shopping