P2138 Throttle/Pedal Pos Sensor/Switch D/E Voltage Correlation

ncarey265

Senior Member
Joined
Jan 17, 2018
Messages
58
Reaction score
4
Your Mercedes
C-Class c220 sport bluetech 64 plate 2.1L
Hi all again!

Driving home from work and got the dreaded engine management light. Followed my messages that my collision prevention assist plus not working. Car went into limp mode even worse limb mode then I've experienced before.

I plugged it in and got P2138 Throttle/Pedal Pos Sensor/Switch D/E Voltage Correlation. Were do I start with this and ideas/ help greatly appreciated.

Car is 2014 w205 c220

Thanks
Neil
 

Uncle Benz

Senior Member
Joined
Mar 31, 2006
Messages
4,220
Reaction score
3,548
Age
53
Location
West Sussex
Your Mercedes
Mainly Mercedes
Sounds like a throttle pedal fault to me. These are double safe by design. One potentiometer tracks up and the other tracks down. The output on one ranges 0-5v and the other 5-0v. The checksum of the two values should always add up to 5v. Something is wrong with yours.
 
OP
N

ncarey265

Senior Member
Joined
Jan 17, 2018
Messages
58
Reaction score
4
Your Mercedes
C-Class c220 sport bluetech 64 plate 2.1L
  • Thread Starter
  • Thread starter
  • #3
Would you suggest a new throttle pressure sensor fitting?
 

Uncle Benz

Senior Member
Joined
Mar 31, 2006
Messages
4,220
Reaction score
3,548
Age
53
Location
West Sussex
Your Mercedes
Mainly Mercedes
I'd be looking closely at the throttle pedal itself. It is all housed in the one unit. You'll find it on the floor in the drivers footwell ;)
 
OP
N

ncarey265

Senior Member
Joined
Jan 17, 2018
Messages
58
Reaction score
4
Your Mercedes
C-Class c220 sport bluetech 64 plate 2.1L
  • Thread Starter
  • Thread starter
  • #5
what am I looking for in doing that then?
 

Uncle Benz

Senior Member
Joined
Mar 31, 2006
Messages
4,220
Reaction score
3,548
Age
53
Location
West Sussex
Your Mercedes
Mainly Mercedes
If you have a diagnostic machine with live data you can look at the output of the pedal, check for any anomaly. If you don't it is a bit of a leap, but pedal faults are reasonably common.
 

Steve@Avantgarde

Forum Supporter
Authorised Forum Supporter
Joined
Dec 8, 2009
Messages
7,314
Reaction score
1,955
Location
Bristol/Somerset
Website
www.avantgarde-automotive.co.uk
Your Mercedes
E300 Coupe AMG Line PP/NE, SLR McLaren Roadster, SL55 & C32AMG
There is a common fault with these and a TIPs document, usually a new pedal, replacement wiring pins and an update of software. Effecting all the range.
 
OP
N

ncarey265

Senior Member
Joined
Jan 17, 2018
Messages
58
Reaction score
4
Your Mercedes
C-Class c220 sport bluetech 64 plate 2.1L
  • Thread Starter
  • Thread starter
  • #8
Oh jeez looks like it's gone over my head lol

So I have done an ecu reset not sure if this has worked yet as not been out in the car. I was thinking if this doesn't work to replace the throttle pressure sensor? As my research suggests this is 99.9% the problem.
 

Steve@Avantgarde

Forum Supporter
Authorised Forum Supporter
Joined
Dec 8, 2009
Messages
7,314
Reaction score
1,955
Location
Bristol/Somerset
Website
www.avantgarde-automotive.co.uk
Your Mercedes
E300 Coupe AMG Line PP/NE, SLR McLaren Roadster, SL55 & C32AMG
Not really, like I said, there is an issue with throttle pedals across the range and 70% is wiring related. There is high resistance through the pins. So you need to replace the wiring pins and update the software. It could be the pedal, but its an expensive guess.

It will be an Indy specialist job at the least.
 
OP
N

ncarey265

Senior Member
Joined
Jan 17, 2018
Messages
58
Reaction score
4
Your Mercedes
C-Class c220 sport bluetech 64 plate 2.1L
  • Thread Starter
  • Thread starter
  • #10
After resetting my ecu and clearing the codes it's not come back on I'm hoping this has fixed it. I'll keep you posted.
 
OP
N

ncarey265

Senior Member
Joined
Jan 17, 2018
Messages
58
Reaction score
4
Your Mercedes
C-Class c220 sport bluetech 64 plate 2.1L
  • Thread Starter
  • Thread starter
  • #11
This is idle readings
 

Attachments

  • Screenshot_20190613-163532_Torque.jpg
    Screenshot_20190613-163532_Torque.jpg
    184.2 KB · Views: 16

ajlsl600

Senior Member
Joined
Nov 18, 2013
Messages
9,031
Reaction score
6,029
Location
france
Your Mercedes
clk3202001,sl6002003 with everything regrettably sold ,A class 170cdi auto. NG/TF1800 ML250
uninformed ,but if idle to full throttle is near 0-20%-100% then 50% at idle seems odd. someone, just about anyone in this case ! will be along who knows better.
 

Oldspanners

Senior Member
Joined
Oct 30, 2017
Messages
1,487
Reaction score
1,598
Location
Normandy
Your Mercedes
C CLASS 2004 C180
Can anyone else expand on this? Is this not normal?
As Steve said there is a problem with throttle pedals and their connectors. 50% is obviously half throttle and not normal for idle, this is symptomatic of the problem. You could change the pedal assembly and find out the connectors are the problem, so unless you have a way of testing it it's a guess as to what the problem is.
Here is a link to a WIS document https://mbwis.net/en/doc/7054324 check if it's your model I just had to guess.
 
Last edited:
OP
N

ncarey265

Senior Member
Joined
Jan 17, 2018
Messages
58
Reaction score
4
Your Mercedes
C-Class c220 sport bluetech 64 plate 2.1L
  • Thread Starter
  • Thread starter
  • #16
As Steve said there is a problem with throttle pedals and their connectors. 50% is obviously half throttle and not normal for idle, this is symptomatic of the problem. You could change the pedal assembly and find out the connectors are the problem, so unless you have a way of testing it it's a guess as to what the problem is.
Here is a link to a WIS document https://mbwis.net/en/doc/7054324 check if it's your model I just had to guess.

Thanks for that I'll repalce the pedal assembly easy enough fix. Any idea were I can get one from? And how much I'm looking at to buy one? Thanks.
 

Oldspanners

Senior Member
Joined
Oct 30, 2017
Messages
1,487
Reaction score
1,598
Location
Normandy
Your Mercedes
C CLASS 2004 C180
Thanks for that I'll repalce the pedal assembly easy enough fix. Any idea were I can get one from? And how much I'm looking at to buy one? Thanks.
https://mercedes.7zap.com/en/eu/fg/car/
Put your VIN in the link, go to Control and find the part number that fits your car then have a look on ebay or contact a dealer direct MB Grangemouth or Newcastle are usually helpful and Grangemouth may give you a MBO DISCOUNT.
But this may not be the problem!
 
OP
N

ncarey265

Senior Member
Joined
Jan 17, 2018
Messages
58
Reaction score
4
Your Mercedes
C-Class c220 sport bluetech 64 plate 2.1L
  • Thread Starter
  • Thread starter
  • #18
the image below is what it was showing before I even turned the engine on now that cant be right?
 

Attachments

  • Screenshot_20190614-215116_Torque.jpg
    Screenshot_20190614-215116_Torque.jpg
    190.7 KB · Views: 11

Oldspanners

Senior Member
Joined
Oct 30, 2017
Messages
1,487
Reaction score
1,598
Location
Normandy
Your Mercedes
C CLASS 2004 C180
the image below is what it was showing before I even turned the engine on now that cant be right?
Certainly big trouble in the throttle area. You can try removing the pedal and cleaning the connector just to see if it makes any difference and prove that at least you are on the right track.
 
OP
N

ncarey265

Senior Member
Joined
Jan 17, 2018
Messages
58
Reaction score
4
Your Mercedes
C-Class c220 sport bluetech 64 plate 2.1L
  • Thread Starter
  • Thread starter
  • #20
Would you say the pedal is certainly the problem based on those readings with the engine turned off? What's the other likely causes? Tps? And pedal fir what they cost I can just repalce both. If there no chance if could be something else.

What would you suggest cleaning the connectors with? Thanks for all your help/ advice its greatly appreciated.
 


GAD was founded in 2009 where we developed bespoke ECU Remapping software for motorsport clients, moving forward, we have extended to road vehicles for both performance and economy,
contact GAD Tuninghttp://www.GADTuning.co.ukto discuss your requirements.
Top Bottom