I would like to try and get some information on the accelerator pedal.

Does this read by a variable resistor, or does it work by a hall sensor?



I ask, because my Cayenne seems difficult to drive smoothly at low speeds and now days where I live, towns and housing areas are restricted to 30kph.

At some areas that are 50kph I can use the cruise control, but it will not engage at lower speeds.

So, trying to drive slowly, the Cayenne always wants to take off (which is fun, but not good for the licence ).

I have noticed that after start and when the idle has settled, if I gently press the accelerator (to get 1000rpm, for example), the revs rise and then drop back down while still holding the accelerator pedal in the same place.

Press a bit more and revs go up and then back down again, to a point where I have pressed enough times (by small amounts) to hold and maintain 1000rpm (1000rpm is just to highlight the problem, it could be 1500, 2000 etc).

This makes me think, that maybe the electronic part of my accelerator pedal is worn.
Or at a wild thought, maybe the sports exhaust that is fitted (I did a post on that).

Or is this normal for a 2003 Cayenne twin turbo.

Is fully serviced with new plugs, coils, oil and filters. New battery and under carpet wiring connections sorted. No codes being shown on scanning. Otherwise, drives really well.

 

Try recalibrating the throttle body...

This may work for the Cayenne.

 

Get a scan tool and view live values for thottle pedal position, throttle body plate position, and maybe even MAF values and see what the numbers are doing.

 

I guess these values will be in volts?
If that is the case, do you have any idea on what values I should be looking for.

 

I don't. I think what you should be looking for is values that increase with more pedal, whereas if the values go up then fall.down while you're still holding the pedal in the same position you'll be able to tell if it's the pedal position sensor or the throttle.body sensor that's misbehaving.

 

Santa Cruz, I have a similar issue. It seems sporadic on my 05 CTT. Sometimes is ok, but for example, right not its very herky jerky. Power is fine, its in in between speeds, coming off throttle, back on, etc.
I can see in my ICARSCAN that at about 1/2 the pedal travel im getting 100% throttle plate actuation, which would explain the ON-OFF behavior.
Also, If I try to just barely increase the throttle and hold it around 1000-1500 rpm, it bounces up and down while Im holding the pedal perfectly still, just as you mentioned.
I replaced the throttle body, which includes the TPS, and that didnt make a difference, maybe a bit smoother.
I have done the throttle adaption via ICARSCAN and the old fashion way with turning the key and waiting the 1 min or so.
Ive done the tranny reset and no improvement. I havent tried the relearn yet with all the stops and starts, and shifts etc. as noted in the one link below, ill try that next.
So I started thinking about the pedal potentiaometer as well, so I might just try replacing the pedal assembly and see if that helps. perhaps the contacts/traces in there arent perfect anymore.

Here are 2 threads where I added to the discussion with issues similar to yours, and some things to try:
https://rennlist.com/forums/cayenne-...tle-angle.html
https://rennlist.com/forums/cayenne-...ody-issue.html

If you try anything and it works, let us know.
If you have already solved this problem, since this thread is old, please let me know as well!

 

My car also has a sometimes wonky throttle pedal feel. I have done zero research into this for my own car, but I’m interested to see what you find!

 

No, I haven't solved it as yet, I kind of live with it. But it is not right.
I will first do a live data with my scan tool to see what the values are and if that shows or does not show anything, then I think my plans will be to remove it, measure resistance and have a look inside to see if there is any wear.
If it's a wiper on a resistive track, you can sometimes get away with moving the wiper position or the track position to run on an unworn section. (Used to be the trick with the old bosh injection with the 'flapper door' inlet.
I will post any findings when I get round to doing it.

 

What you describe at idle is normal. Older cars had an idle control solenoid that was responsible for maintaining idle speed. More modern cars with electronic throttles use the electronic throttle to stabilize the idle. So, when you’re at idle if you add the smallest amount of throttle, the ECU will continue to seek idle and thus the rpm’s drop down as you describe.

Follow the advice on hear about doing a throttle adaptation, and/or clean the throttle body.

 

Thank you. Noted.
I will give this a try first.
I did try the throttle adaption once before, but fear I may have done it wrong.

 

Deposits of dirt, oil, and gunk can build up around the throttle butterfly, which can result in erratic movement of the valve. By exposing the butterfly you can rotate the butterfly valve and check to see if it rotates smoothly. If not, clean it. Then retest.

 

In my case I have a brand new throttle body, also my original one I cleaned many times.
I have also done the adaptions of the throttle body, and the pedal, with the above methods, and through my ICARSCAN tools, with no change.

However, since you mentioned JAGMAN1 that this is normal, I no longer need to solve that problem (which I thought WAS a problem and isnt), but I still have a very sensitive throttle and get 100% plate actuation at 1/2 the pedal travel (like an on off switch). Might still be something unrelated to any of this.

Im going to recheck with my smoke machine for leaks.

I also order a new Hella gas pedal assembly, will try that and send back if it doesnt make a difference.

 

Just to be clear, what I was describing as “normal” was the behavior at or near idle when the pedal is depressed very very little. As for the other part, 100% plate actuation at 1/2 pedal travel, I don’t have data on that. Keep in mind that electronic throttles are not linear. They are designed to be non-linear to improve driveability. And I don’t have data to describe what is or is not normal.

 

Yep, I understood you, just the "hunting" of the rpms with light throttle application

Thanks again for the info!

 

Opening the throttle valve after removal for cleaning is okay?
I thought by manually opening it, it could be damaged, or is that not the case with the 955 turbo?