BAS/ESP intermittent issue. Vehicle loses acceleration

Sofia Prentzas

Asked by Jun 13, 2014 at 02:00 AM about the 2001 Mercedes-Benz SLK-Class SLK320

Question type: Maintenance & Repair

My 2001 Mercedes SLK320 is experiencing an intermittent BAS/ESP issue. When
driving, the vehicle loses acceleration but not power, engine still runs and I can still brake.
Turning the steering wheel all the way to the left lock position and all the way to the right
lock position does no good. Unhooking the battery did not work either. Took it to a shop
scanned the computer and came up with various codes. The shop manager recommend I
replace the brake lamp switch first and that did no good. Took it back and they suggested
I replaced the K40 Relay. That also did not fix the problem. Finally I got fed up and did
not take the car back to that shop as I felt they did not know what in the heck they were
doing. Mind you they specialize on Mercedes yet they can't pinpoint the problem. Odd.
From then on I took matters into my own hands. The most recent part changed was the
accelerator pedal sensor (Code P203B/P0221) I hired a mobile mechanic to change it?
however he told me this is probably not going to fix the issue but worth a try. Well he was
right this also did not fix the problem.

If this helps the last time I was at the shop they pulled 2 codes:

P203B in ME for faulty accelerator pedal sensor (changed part)
C1022 - CAN communication for faulty ABS Control Module

They wanted $1600 to change both parts (HA HA yeah right I don't think so) I can
recognize when someone is trying to screw me over. This was quite evident so I left and
never went back.

Also note: My ABS light has not come on once since having this problem only the
BAS/ESP light. Not sure if that means anything. Check engine light has not come on
either since having this problem.  

Another note: The BAS/ESP light does not come on first and then the car loses
acceleration, it happens at the exact same sequence, THE light comes on and car stalls
at the exact same time so it is very unexpected and dangerous. When the car stalls I just
turn the car off real quick and restart it and it lets me drive again until it decides to cut out
again. The car seems to be driving just fine. It just cuts off. Mobile guy is really betting
this is bad wiring but I'm just all over the place in my mind and don't know to think

Lastly after speaking with the mobile mechanic who changed out the accelerator pedal
sensor he recommends I have him take all my wheels off and have him check all of the
ABS sensor harnesses for faulty wiring causing a bad connection. He seems to know
what he is talking about but I thought I could get a second opinion and possibly gathering
information that I was unaware of. I have received so many different possibilities as to
what could be causing this issue but I am at my wits end with this problem I don't know
what else to do at this point and don't have an indispensable amount of money to spend
on this.

PLEASE HELP! I really need it!!

Thank you very much!!

7 Answers


Check the Forum at Theres plenty of SLK afficionados there who encountered this issue and will give you sound advice as to both DIY solutions, or reasonable repair cost estimates. Its the best site going for any SLK owner.

6 out of 6 people think this is helpful.
Jesse Yin

Hi I met exact the same issue - 2001 mercedes ML320, also replaced pedal accelerator sensor which did not work. Looking for guidance please!

9 out of 9 people think this is helpful.
Daniel Jang

i have the same problem with my ml320 2001. need help

4 out of 4 people think this is helpful.
Daniel Jang

it seems that it is related with sudden brakings.

4 out of 4 people think this is helpful.

My 2001 ml320. Sudden and high to low speed braking always cause the same problem. Solution??? Thanks dan

1 out of 1 people think this is helpful.
Sofia Prentzas

Hey Guys, Alright so after 2 years of dealing with this overwhelmingly frustrating intermittent acceleration issue, my mechanic finally pin pointed the problem. It was a faulty Throttle Body. I believe this has to do with fuel injection. Ultimately he told me oil got into the throttle body which was causing the problem. Before my mechanic switched out the throttle body, he had to change out my entire pedal assembly because he pulled a fault code. The reality with this problem is there may be more than one culprit causing the issue and in my case that is what happened. Changing only the sensors will not work. You have to completely switch out these parts. DO NOT BUY USED PARTS BUY THEM BRAND NEW OEM BOSCH! This is not a one day fix and I would recommend taking your car to a knowledgable mechanic to deal with this issue as this is not something you should try to fix yourself.Trust me we tried. Also note that when I was experiencing this problem my check engine light NEVER came on. It should have but it didn't and that's probably because of the faulty sensors. After the throttle body was switched out the check engine light still did not come on. HOWEVER after the fact, I drove about 2 drive cycles and my check engine light finally came on and pulled 3 codes. I am mentioning this because you too may experience this. The 3 codes I pulled were: P0410 PO170 PO173 You can find the Throttle body assembly on for about $305 AND you can qualify for $15 off since the cost is over $300. The code for the $15 off is: (SAVE15) Below is the direct link for everyone's convenience: Hope this helps!! Happy Holidays everyone!

3 out of 3 people think this is helpful.

Hello Sofia! I would like to check to see if you are still having issues with acceleration or not? Just want to see if changing the throttle body did indeed repair your issue?

2 out of 2 people think this is helpful.

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