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Oh good
Perhaps some simple sensor pinout measurements can provide baselines for good or bad device condition
Wonder if the static impedance at room temp will be different between the new and old?
Just thinking out loud
 

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Hello guys,

I am desperately looking for answers. I've been to my local Mercedes-Benz dealership about 4 times for this issue and they are unable to tell me with certainty what the issue is. So I'm here to see if anyone else has experienced something similar and if they were able to get it resolved.

About 3 months ago, on a typical day driving to work, I accelerated by pressing the gas pedal down a bit to overtake someone. As the car picked up speed, suddenly it had a violent jerk, almost like I got hit from behind. I thought this was a one off situation as I tried to replicate it again and again and nothing happened.
Over time, the issue became more noticeable and more frequent. It seemed that when I would press the accelerator down to pick up speed fast, the car would violently jerk in 3rd, 4th, 5th and sometimes even 6th gear. The jerking would not stop until I let go of the accelerator. The RPM also stays steady around 4000-5000. At this point is when the car then shifts gears and accelerates as it normally would. There were no check engine lights so the dealership can't scan for any codes. The car is a 2014 CLA 45 AMG that is driven 71000km.

The dealership performed a update to the TCU, and even performed a transmission service however the issue still persists.

After all this they seem to suggest that it is a fault with the dual clutch... but they are not sure.

Since the car is out of warranty, and me having poured a few thousand already into them experimenting fixes, I want to get a better idea of what the issue is and what could be causing it before I sign off on anymore suggestions from this dealership.

So has anyone else had similar issues? What did you do to get it fixed?
I had this issue before two weeks and I have A45 2015 model I scanned the car and it showed that I have a low fuel pressure and so it’s from the rear fuel pump and it needs to be replaced to solve this issue
 

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Big thank you to all of those who contributed in pinpointing the problem! You guys have no idea how much I appreciate it.

Brought me joy back in driving my car again!
I can’t believe I’ve had the same problem and I was so worried! I’ve taken your advice and got my crankshaft sensor replaced on my A class and no longer have any violent Jerks!! After taking it to two garages and them telling me it will be a case of “ process of elimination” thanks all for this thread!
 

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2014 CLA 250 4MATIC ✨
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Hello guys,

I am desperately looking for answers. I've been to my local Mercedes-Benz dealership about 4 times for this issue and they are unable to tell me with certainty what the issue is. So I'm here to see if anyone else has experienced something similar and if they were able to get it resolved.

About 3 months ago, on a typical day driving to work, I accelerated by pressing the gas pedal down a bit to overtake someone. As the car picked up speed, suddenly it had a violent jerk, almost like I got hit from behind. I thought this was a one off situation as I tried to replicate it again and again and nothing happened.
Over time, the issue became more noticeable and more frequent. It seemed that when I would press the accelerator down to pick up speed fast, the car would violently jerk in 3rd, 4th, 5th and sometimes even 6th gear. The jerking would not stop until I let go of the accelerator. The RPM also stays steady around 4000-5000. At this point is when the car then shifts gears and accelerates as it normally would. There were no check engine lights so the dealership can't scan for any codes. The car is a 2014 CLA 45 AMG that is driven 71000km.

The dealership performed a update to the TCU, and even performed a transmission service however the issue still persists.

After all this they seem to suggest that it is a fault with the dual clutch... but they are not sure.

Since the car is out of warranty, and me having poured a few thousand already into them experimenting fixes, I want to get a better idea of what the issue is and what could be causing it before I sign off on anymore suggestions from this dealership.

So has anyone else had similar issues? What did you do to get it fixed?
Same things happened to me :( never figured out what happened but eventually stopped.
 

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Hello guys,

I am desperately looking for answers. I've been to my local Mercedes-Benz dealership about 4 times for this issue and they are unable to tell me with certainty what the issue is. So I'm here to see if anyone else has experienced something similar and if they were able to get it resolved.

About 3 months ago, on a typical day driving to work, I accelerated by pressing the gas pedal down a bit to overtake someone. As the car picked up speed, suddenly it had a violent jerk, almost like I got hit from behind. I thought this was a one off situation as I tried to replicate it again and again and nothing happened.
Over time, the issue became more noticeable and more frequent. It seemed that when I would press the accelerator down to pick up speed fast, the car would violently jerk in 3rd, 4th, 5th and sometimes even 6th gear. The jerking would not stop until I let go of the accelerator. The RPM also stays steady around 4000-5000. At this point is when the car then shifts gears and accelerates as it normally would. There were no check engine lights so the dealership can't scan for any codes. The car is a 2014 CLA 45 AMG that is driven 71000km.

The dealership performed a update to the TCU, and even performed a transmission service however the issue still persists.

After all this they seem to suggest that it is a fault with the dual clutch... but they are not sure.

Since the car is out of warranty, and me having poured a few thousand already into them experimenting fixes, I want to get a better idea of what the issue is and what could be causing it before I sign off on anymore suggestions from this dealership.

So has anyone else had similar issues? What did you do to get it fixed?
Did you ever replaced the engine and tranny mouths??
 

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Thanks everyone for this thread. I too had the dreaded jerk from accelerating and managed to fix it by changing the Crankshaft Position Sensor. Funny I rectified the problem before I even had a chance to read any error codes, and sure enough in the obd error code history there was a P033904 recorded from 3 weeks prior.

My S205 C350e has a slightly different location for the CPS and it is quite awkward to unscrew from beneath the vehicle but it is doable with a degree of patience.

But all is well now and I have a happy car, cheers
 

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2014 CLA 250 4MATIC ✨
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Perfect, thank you so much. I honestly hope this is the issue. I'm going to get it looked at by the tech. Will report back with what they say and if it fixed the issue. I'd much rather this than go with the dual clutch replacement that they were suggesting. I never could understand how it would be the dual clutch as this would happen even in Manual mode without shifting any gears...

This is such a relief.

Thanks a bunch!
 

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Hey all. I think I am having the same issue but want to poll the audience. Car used to violently jerk on heavy loads even in lower speeds and higher - brought it in for service, they patched up a couple cables, performed a software update, and called it a day...the jerks in lower speeds stopped, but still noticing if I'm trying to go from around 110 km/h and accelerate to overtake, the jerks come back, and if I keep trying to accelerate, I'll lose all transmission control until the car completely stops and goes back to 1st gear. Planning on going back to the service center and having them replace the crankshaft position sensor because it seemed to work for y'all but want to make sure the problems are similar! 2014 CLA 250 here.
 

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Hello,

I am also having an issue with my crankshaft position sensor on my 2014 CLA 45 w/ 87K miles. Codes are P0339(04) & P0339(00).

I had my crankshaft position sensor replaced with an OEM sensor from my local MB dealership. The vehicle is still going into limp mode (stuck in comfort with no power output or downshift) even after I replaced the sensor.

Is it possible my Starter Battery could be causing this as my sensor is not receiving enough voltage/power to operate correctly.

Please anything helps I cant even drive the vehicle without immense jerking/stalling out.
 

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C250 W205 M274
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Oh well, this issue is not only happening on the CLA45, I have a C250 and at the begging I used to love the car now I very disappointed because I am afraid to accelerate it hard because the transmission jerks violently. Like all the CLA45's in this thread, my C250 also jerks pretty badly under acceleration, for example if I am slowly merging on the freeway and accelerate from 60 then the car jerks so bad that it feels as if someone just hit me from behind and it is really embarrassing, it normally happens at D3 and D4; I did a transmission service and it didn't help, then I changed the spark plugs and it did help for a while but the issue came back again, I took the car to a Certified Mercedes mechanic and he had no clue, the car has only 80K, it is a C250, 2015.

Is changing the crankshaft position sensor a DIY thing or something only a Mercedes dealer can do?
 

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I probably have the same issue, but is it the crankshaft position sensor or camshaft position sensor ?
I having hard time finding the right part.

And is it easy to change at home ? Can t find where it is exactly.
 

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I got a P0299 today...

P0299 is a diagnostic trouble code (DTC) for "Turbo / Supercharger Underboost Condition".

Doesn't sound good...
 

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I got a P0299 today...

P0299 is a diagnostic trouble code (DTC) for "Turbo / Supercharger Underboost Condition".

Doesn't sound good...
Have you tried checking your accelerator pedal? my car used to jerk similar to the very first post, took my car to a dealer then to a Mercedes specialist and nothing, all they did was to run a scanner found no faults and recommended to change plugs, transmission service but in the end the problem was still there, one day I read somewhere that the accelerator pedal becomes faulty on these cars, the terminals become corroded somehow, I went ahead and removed the pedal, took me 5 minutes to remove it, sprayed carby cleaner and all good, no jerking whatsoever.
 

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I got a check engine light, not sure if it is the same thing.

I will the intake and what i can tomorrow, and take an appointment to a garage of i don't see anything.
 
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