Throttle Position Sensor or Throttle Body Actuator
Thread Starter
Newbie
Joined: Aug 2015
Posts: 13
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From: UK
CLK430 Cab 2001 & Volvo 480 1989
Throttle Position Sensor or Throttle Body Actuator
My throttle is only working up to about 28%
It is a smooth increase till that point but any further movement of the accelerator is ignored.
I have no engine light or codes and provided I don’t go above 28% or press the kickdown it drives OK.
Is this likely to be the Throttle Position Sensor or the Throttle Body Actuator? I don’t know where the scan tool reads from.
Or could it be something else? Any help would be appreciated.
It is a smooth increase till that point but any further movement of the accelerator is ignored.
I have no engine light or codes and provided I don’t go above 28% or press the kickdown it drives OK.
Is this likely to be the Throttle Position Sensor or the Throttle Body Actuator? I don’t know where the scan tool reads from.
Or could it be something else? Any help would be appreciated.
Thread Starter
Newbie
Joined: Aug 2015
Posts: 13
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From: UK
CLK430 Cab 2001 & Volvo 480 1989
If you read my post it says “I have no engine light OR CODES” I did think about using my finger to decide if I had codes but chose to scan it instead.
Moving forward my question is what does the scanner read when its quotes the percentages, the TPS (most likely bearing in mind the name) or the TBA. I will find this out when I work on the car this weekend but would have saved me time if someone else could have confirmed.
The added information was in case someone out there had had the same problem and could given a quick solution.
There is also no reason for a code because as I stated the car drives normally (my other post has been sorted) so as far as the car (ECU) is concerned I could be a 90 year old granny that never presses the accelerator over 28% so why would it give a code.
Moving forward my question is what does the scanner read when its quotes the percentages, the TPS (most likely bearing in mind the name) or the TBA. I will find this out when I work on the car this weekend but would have saved me time if someone else could have confirmed.
The added information was in case someone out there had had the same problem and could given a quick solution.
There is also no reason for a code because as I stated the car drives normally (my other post has been sorted) so as far as the car (ECU) is concerned I could be a 90 year old granny that never presses the accelerator over 28% so why would it give a code.
Last edited by eye of ra; Nov 17, 2017 at 02:33 PM.
Junior Member
Joined: Oct 2016
Posts: 59
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From: Central PA
1986 Porsche 911 Coupe, a 2002 CLK320 & 2013 C300
Try having someone press the accelerator pedal and see if there's a physical issue with the cable, it' the low tech thing I'd try first since you're not getting code errors or and there's no engine light. A physical restriction would explain that at least.
Thread Starter
Newbie
Joined: Aug 2015
Posts: 13
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From: UK
CLK430 Cab 2001 & Volvo 480 1989
Thank you for the advice.
Having now done some research on electronic throttle controls it would appear I may have been calling things by their wrong names.
What I was calling the TPS would be better called the Throttle PEDAL position sensor and the TPS is part of what I was calling the throttle body actuator.
I have moved the TPPS by hand and as with the pedal the scan tool shows a steady percentage increase till about 28% after that as you move it further there is no increase in percentage.
As I have no codes my theory is the TPPS not the TPS or Actuator. However before throwing money at it does anyone have the voltage and/or resistance values of the terminals?
From what I understand all W208 where the same but if it helps it’s a 2001 430.
Having now done some research on electronic throttle controls it would appear I may have been calling things by their wrong names.
What I was calling the TPS would be better called the Throttle PEDAL position sensor and the TPS is part of what I was calling the throttle body actuator.
I have moved the TPPS by hand and as with the pedal the scan tool shows a steady percentage increase till about 28% after that as you move it further there is no increase in percentage.
As I have no codes my theory is the TPPS not the TPS or Actuator. However before throwing money at it does anyone have the voltage and/or resistance values of the terminals?
From what I understand all W208 where the same but if it helps it’s a 2001 430.
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Joined: Nov 2001
Posts: 1,258
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From: Boston North Shore
2001 CLK320 Cabrio
Did you see this thread http://www.benzworld.org/forums/w163...-test-tps.html ?
Note the MB WIS info in post # 5 .
A faulty pedal position sensor would store a P1542 diagnostic fault code. I believe our W208s use the Hall Effect sensor and trouble shooting is via voltage (not resistance) measurement. I've included some additional on this.
MBWorld Fanatic!
Joined: Feb 2011
Posts: 2,562
Likes: 197
From: Austin, TX
2006 E55, 2012 GLK350 & 1992 190e sportline
If you read my post it says “I have no engine light OR CODES” I did think about using my finger to decide if I had codes but chose to scan it instead.
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Thread Starter
Newbie
Joined: Aug 2015
Posts: 13
Likes: 0
From: UK
CLK430 Cab 2001 & Volvo 480 1989
Did you see this thread http://www.benzworld.org/forums/w163...-test-tps.html ?
Note the MB WIS info in post # 5 .
A faulty pedal position sensor would store a P1542 diagnostic fault code. I believe our W208s use the Hall Effect sensor and trouble shooting is via voltage (not resistance) measurement. I've included some additional on this.
I managed to find some info elsewhere on the Throttle Body/Throttle Position Sensor and came to the conclusion that something in-between was at fault.
While searching for the reason for my fault I discovered why I didn’t have a code, because I don’t have a fault, it’s a “feature” when in neutral the throttle butterfly movement is restricted as a rev limiter to protect the engine when not under load. Took the car for a drive with the scanner connected and throttle position went to 100%.
I was assuming the 28% throttle when tested in my garage was a fault and causing my lack of power while driving, when it wasn’t.
Turned out the lack of power while driving was the cheap ebay MAF I purchased when I did have an engine light and code.
So my problem was sorted without wasting money (except the c**p MAF) with the help of one or two people here who genuinely wished to help (Carsoft does look interesting) and I wish to thank them, along with some searching and a genuine MAF.
Investigation should be the first thing you do. If the FIRST piece of advice is spend/waste money at the dealer why not just answer all questions with “take your car to your local dealer and they will fix it”. I accept if after some investigation you are getting nowhere a Star scan is probably a good idea.
Last edited by eye of ra; Dec 6, 2017 at 01:47 PM.
MBWorld Fanatic!
Joined: Feb 2011
Posts: 2,562
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From: Austin, TX
2006 E55, 2012 GLK350 & 1992 190e sportline
I am glad you found the answer to your problem.
I would not suggest that you take a car to the the dealer for repairs. I for one don't like to buy parts I don't need. In a situation like yours a STAR scan would point me to the problem or at lest the right direction. The dealer has a scan system that is far superior to any OBD scanner. Even if you are not seeing a light or a code there is much stored info you can not access with a OBD scanner. I have actually caught things on the STAR scan the indy did not pick up on and saved me thousands. Also you have to admit that someone who works on MB for a living is probably better suited diagnose a complex problem than your average armchair mechanic.
Investigation should be the first thing you do. If the FIRST piece of advice is spend/waste money at the dealer why not just answer all questions with “take your car to your local dealer and they will fix it”. I accept if after some investigation you are getting nowhere a Star scan is probably a good idea.
