Vehicle Knocking/Jerking Issue with High RPM
08-30-2023, 03:08 PM
#1
Newbie
Thread Starter
Vehicle Knocking/Jerking Issue with High RPM
Hey everyone, writing about an issue I’m facing with my 2015 C300 4Matic, approx. 79,500 miles.
For the past few months now (~2,000 miles worth of driving) I’ve noticed some distinct jerking/knocking when I exert sharp acceleration on the car. This occurs around after around 3,000 to 4,000 rpm and then a visible jerk/knock would occur. After about a couple of times when this happens on a given drive, it feels like the turbo shuts off and then when I floor it, the car gradually accelerates sometimes not reaching past 2,000 rpm.
I took it to a local Benz dealership and they essentially told me no check engine lights were on, couldn’t replicate the problem, and then just sent me home (I ate the like $200 diag fee which sucked).
I decided to change the battery as well to see if that would solve, but still with a new battery this issue still persists. A note as well here is that after the repeated knocking and what I gather as the turbo shutting off, the auto start/stop light is disabled. Usually after waiting some time and after stopping the car and starting again, the drive behaves like normal (until it happens again).
Has anyone faced this issue before or has any ideas on what I can do to solve this issue? I’m taking the car at the end of September for my 80,000 servicing and got a hold of a service advisor at another local Benz dealership with this as a specific issue to examine.
Any information/insights would be much appreciated, thanks so much!
For the past few months now (~2,000 miles worth of driving) I’ve noticed some distinct jerking/knocking when I exert sharp acceleration on the car. This occurs around after around 3,000 to 4,000 rpm and then a visible jerk/knock would occur. After about a couple of times when this happens on a given drive, it feels like the turbo shuts off and then when I floor it, the car gradually accelerates sometimes not reaching past 2,000 rpm.
I took it to a local Benz dealership and they essentially told me no check engine lights were on, couldn’t replicate the problem, and then just sent me home (I ate the like $200 diag fee which sucked).
I decided to change the battery as well to see if that would solve, but still with a new battery this issue still persists. A note as well here is that after the repeated knocking and what I gather as the turbo shutting off, the auto start/stop light is disabled. Usually after waiting some time and after stopping the car and starting again, the drive behaves like normal (until it happens again).
Has anyone faced this issue before or has any ideas on what I can do to solve this issue? I’m taking the car at the end of September for my 80,000 servicing and got a hold of a service advisor at another local Benz dealership with this as a specific issue to examine.
Any information/insights would be much appreciated, thanks so much!
11-03-2023, 03:14 PM
#2
Newbie
Thread Starter
Update - I finally got to the bottom of it from a great local Benz mechanic and turns out it was rooted in a crankshaft position sensor malfunction along with a pedal value sensor (accelerator) malfunction. Was a tough pill to swallow but so glad this issue that has been plaguing me for so long has finally been resolved - car drives good as new now.
For good measure, reset the TCU as well after all said and done. Hope to keep this car forever!!
For good measure, reset the TCU as well after all said and done. Hope to keep this car forever!!
