Any codes?
PPS cost $140 for 3.2l

 

No codes tripped on my carsoft 7.4.

Thanks

 

That would be strange.
Such a failure leaving no errors on the computer for 2002 model.
I would try another scanner just to make sure.
PPS error clears itself after few restarts.

 

Thanks , the hesitation is consistent when the engine is cold so if there was a code, it would be tripped every time. I thought it may have been dirty injectors or carbon build up in the intake in the past but given that the throttle completely gave up. I'm suspecting that it's an electrical issue. Still , it should throw an error and i'm surprised that it has not. I'll give it a couple of days in case someone else has experienced the same issue and then maybe run it to the dealer.

Thanks again.

 

Did you ever find the issue? Its 28F here in San Antonio right now and my car is experiencing the same issue. There is a delay in throttle response and if i push the gas a bit to far in it responds and spins the tires.

 

I would check/clean the throttle body (butterfly). I would suspect the cold is causing some carbon or general film on the mechanical components to become too viscous for the throttle motor to smoothly operate the butterfly.

Could be in the electric motor itself but I'd start with some good ole fashioned cleaning of the butterfly.

 

If I was going to attack this - at that mileage Stabil Marine Fuel Stabilizer ($9 1/2 bottle per intructions) - change out fuel filter with Bosch/Mann ($35 and a few hose clamps) - check air filter/replace (Mann/Hengst ($16) - clean purge valve with MAF cleaner ($9 a can) - any signs of "choking idle" coming to a stop then clean MAF with same cleaner + then have cats checked front + rear rubber/mallet + IR test at temp (free) when cold called "cold rocks syndrome" -

 

Hi guys, I replaced the fuel filter fairly recently and also the air filters and the transmission filter. This issue appears to be a problem with the drive by wire system. As I said,I lost all control of the throttle... as in I could have my foot stomped on the padal and the car would just idle.

I've still not plugged my scanner in to see if it could pick up codes, there is no check ending light.

 

There is a cable attached to the accelerator pedal which terminates into a plastic block under the hood (at the throttle control.) What you describe with having no codes indicates that your plastic retaining block is kaput so when you step on the accelerator, the information is not being sent to the drive-by-wire system, but the return spring in the accelerator makes it feel like everything is ok.

You can see the end of this cable right near the master cylinder.

 

Thanks, does this apply if the symptoms are intermittent? As long as I don't stomp on it, the car drives fine and its definitely more noticeable when the engine is cold and the weather is cold.

 

PPS triggers CEL, so I would wait for codes

 

If your code reader has live data, you can check the TPS parameter to see what the throttle position sensor is reading. Sounds like you may be able to reproduce problem. If TPS is showing closed throttle when this happens, I would guess it may be an issue with electronic throttle and linkages. But symptoms don't sound like a TPS problem--if it were, wouldn't car stall instead of just running at idle?

 

I had PPS failing on 2 cars and after initial choke, it would give me about 3/4 of normal power.
Still enough for driving, just no hard acceleration.

 

I was focused on his symptom of an idle response from a stop. How would a bad TPS cause that, if the throttle was working? Maybe I am taking his description too literally, and he is having a poor throttle response coming from a stop, and not an actual idle response.

 

I am always pretty skeptic to human describing technical issues.
Our senses are pretty lousy, so there always is huge error margin.
Still the description are close, but different from my experience, that is why I would wait for codes.

 

Ok so i tried resetting the throttle sensor by doing the following and it seems to have gotten rid of the problem on my car.
1- Turn your ignition to on without starting the car and press the gas pedal all the way in for 5 seconds
2-Without releasing the gas turn the ignition off after 5 seconds.
3- Release the gas.
4-Remove key
5-Restart car

 

I had a similar problem but it didn't matter what the temp was and I was getting a code on the reader. I changed the PPS and the problem was solved.

 

Finally got around to putting a scanner on this (I know right?). No CEL, but some stored code.

P20DD and P20D4

See images for details:

Is there a pedal sensor or is it the TPS? Have a good mind to replace the TPS and see what happens.

 

Hi Al
if the codes are the problem for the hesitation then its the afterburner in the exhaust
the codes are for
P20D4 Mercedes-Benz Exhaust Aftertreatment Fuel Injector "B" Control Circuit High
P20DD Mercedes-Benz Exhaust Aftertreatment Fuel Pressure Sensor Circuit

the systems were originally developed for diesels to reduce the particulates in the exhaust. CARB got hold of the idea and they are now fitted to large high end gasoline engines too
there is an "injector" in the exhaust that will add a little more fuel to the exhaust stream if the cats are running too cool. Can be a problem from cold start if the cats are iffy but should not pose much of a problem on an up to temp car unless the cats are not performing.
I believe it can affect the throttle performance in an effort to reduce the emissions, particularly if the cats are cold, but to be honest I have never played with the system and dont know much about the intricacies. I didnt even know they had fitted it to earlier E55 engines.
cheers
Barri

 

Barri,

Odd, scanner indicates pedal sensor (as pictured). This is a 2002 so maybe they re-used the codes at a later date?

 

I dont know Al - I have never had to play with that system, should be easy enough to check if you have it once you know to look. I checked back for the mercedes specific codes only and that is the only one that came up.

I may also just be confusing the issue as a quick search got this
http://www.justanswer.com/mercedes/1q6zv-mercedes-benz-g500-usa-model-2002-fault-code-p20dd-001.html

which says it is a pedal position fault - Maybe I should just shut up.
cheers
Barri

 

Barri

I appreciate your help (as always). I've looked for a pedal position sensor on worldpac and it's not listed. It should not be hard to hone in on this problem from here on.

Thanks again.

 

Quick update. I cleaned the throttle position sensor and it for the most part fixed the problem but it still bogs down at 4500rpm. I'm going to give it a couple of days to see if it gets better. If not, then I'll replace it.

Thanks again