Wheel-skipping like vibration from rear of the car when accelerating hard from a standstill (S205)

[sk1920]

Just got back my car 4 weeks ago after a major repair from mercedes (hybrid battery replacement). Car was fine for the first 2 weeks and then I noticed an aggressive jerk from the front end one cold morning on my way to work as i launched from a green light.

Subsequently kept happening and was getting worse but random. It wouldn’t let me change gears myself ie paddles were unresponsive. So i did a gearbox reset and that seemed to have sorted the manual shifting issue however the jerking was still happening.

So I did some digging and found that a faulty crankshaft position sensor (A2709050600 in my case) could causing the jerking. I went to mercedes and ordered one and replaced it myself and the jerking seems to have stopped when planting my foot on the accelerator.

However this new strange aggressive vibration from the rear (feels like it might be diff related) when accelerating from a standstill has started happening, completely new and it seems like its coming from the rear.

Any ideas what it might be?
Thanks

 

[LostKiwi]

Take it back to MB.

 

[alexanderfoti]

+1, they have probably dropped something as part of the work (subframe?) and something may have been disturbed.

 

[ernieh]

Your words...'planting my foot on the accelerator'. If I do that too aggressively, the traction control kicks in and I get a vibration. That wouldn't be your problem would it, with your new battery and increased power flow?

 

[mattkh]

However this new strange aggressive vibration from the rear (feels like it might be diff related) when accelerating from a standstill has started happening, completely new and it seems like its coming from the rear. Any ideas what it might be?
Thanks

Have you checked all the wheel bolts on the rears for tightness..?

 

[mioba]

Dealer or Indy to inspect.

 

[sk1920]

Your words...'planting my foot on the accelerator'. If I do that too aggressively, the traction control kicks in and I get a vibration. That wouldn't be your problem would it, with your new battery and increased power flow?

When I first got the car I could launch it at will, zero traction problems and certainly no violent vibrations from the rear. It’s new and strangely doesn’t happen all the time. But I am sure something’s not right.

 

[sk1920]

Have you checked all the wheel bolts on the rears for tightness..?

Yes I have. In fact I had a puncture omw to work yesterday and had to change a tyre at the tyre shop, bolts were fine.

 

[sk1920]

Dealer or Indy to inspect.

Yes that’s the tricky bit. I have extended mercedes warranty about to start soon however the last time i took it in to mercedes for repairs they made themselves look quite incompetent and changed a ptc heater when the car had a message on the dash saying battery malfunction. In the end the had to raise a technical issue with mercedes germany who told them to change the HV battery. So I have somewhat lost confidence in the dealer’s ability to repair my vehicle as it should be.

The other thing is during that same period when my HV battery was shot, my first port of call was indys and everything “mercedes specialist” within a 50m radius were making up excuses and some downright saying they didn’t have the equipment to get in to my vehicle (peculiar I know).

Some even said they weren’t prepared to work on the vehicle as it’s possible to fatally electrocute ones’ self should they make contact with the high voltage system which made me wary about doing DIYs and ultimately bringing it in to mercedes.

And they had the vehicle with them for 76 days out of which they only provided me with a courtesy car for 3 days. Shocking!

 

[alexanderfoti]

"vehicle as it’s possible to fatally electrocute ones’ self should they make contact with the high voltage system"

This is absolutely true. There is a high voltage training course, and special procedures for isolating the HV system when working on it. MB also do not sell certain HV components without confirmation you have completed the training (same for coding)

 

[Tony Dyson]

I had a similar problem with a car about 20 Years ago and it turned out to be, upon hard acceleration from standing, the wheel was momentarily spinning within the tyre until it gained traction! Old tyres, they had to be replaced, put some timing marks on your wheel/tyre rims and monitor.

 

[mioba]

The issue with HV is thats its a relative new tech and indys just dont have the experience and MB are still Insag training thier techs.

If you have MB warranty keep it witb the dealers - let the warranty do its work.

The last think you want is them to say this has been done outside and your warranty is void.

With dealers in this instance you have good fallback when things go wrong. Its thier headache and let them sort it.

 

[DREAMER NO2]

Tony you must have had tubes in the tyres for them to do that. Because the tubeless tyres would have gone down .

 

[Tony Dyson]

Tony you must have had tubes in the tyres for them to do that. Because the tubeless tyres would have gone down .

I don't remember, I do recall I was surprised there was no pressure loss but I've slept a few times since then!

 

[Blobcat]

I don't remember, I do recall I was surprised there was no pressure loss but I've slept a few times since then!

Rim lockers… that’s what you need to stop wheel on rim slippage

 

[LostKiwi]

When I first got the car I could launch it at will, zero traction problems and certainly no violent vibrations from the rear. It’s new and strangely doesn’t happen all the time. But I am sure something’s not right.

When you first got the car was it winter and were the roads slimy with water and salt?

 

[sk1920]

When you first got the car was it winter and were the roads slimy with water and salt?

No it wasn’t winter, I got the car in July. However the issue doesn’t seem to only happen exclusively on slippery surfaces so I am inclined to believe there is more at play here.

I used to own a 528i (auto) and a 325i (manual) all of which I launched all the time so I’m quite familiar with Stability Control restricting power due to loss of traction. This problem doesn’t feel like wheelspin, it feels like driving really fast on an uneven road but I can only feel it from the rear wheels.

And it only happens under hard accelerations, sometimes. But more often than not

 

[LostKiwi]

Have you taken it back to MB yet?
I know you've lost confidence in them but from a Consumer Act perspective they are the ones who you have a contract with.

 

[sk1920]

Have you taken it back to MB yet?
I know you've lost confidence in them but from a Consumer Act perspective they are the ones who you have a contract with.

No I haven’t. My extended warranty starts one month from the date of purchase and I only got it on the 3rd of this month. And honestly I wasn’t sure of making any early claims just yet.

 

[mattkh]

....... This problem doesn’t feel like wheelspin, it feels like driving really fast on an uneven road..?

That feeling would be a bumpy ride feel.
In that case, could it be related to the rear suspension. What do you know about the rear shocks on the car..?