Failed burn out attempt - code P20DD
 

Okay so it has been a year since I purchased the SL65. I drive normally for the most part. But today I thought I would try a burn out for the first time being the year anniversary and all. So I turn off the ESP and mash the gas.
Nothing, car instantly goes to limp mode and I have an error ESP visit workshop in the dash. So I turn off and restart the car and everything is normal. So I try it again, same result. Re start the car and normal again.

So I drive around for about a half hour. Flooring the car from from a roll is no problem. I tried flooring it in second gear with the ESP off and it spun the tires, again no faults. Then I tried from a stop again with the ESP off. This time no faults and holy chit, absolutely roasted the tires in first and shifted into second and smoked the tires till I let off.

When I got home I hooked to the SDS and have a P20DD code. That is pedal position sensor. With everything working well now I cleared the code and will do more testing.

I have a theory. When I tried the first burn out it was on high friction cement. The successful tire fry was on blacktop. I am thinking maybe the high friction overloaded the trans torque limit and went into limp mode.

The blacktop was no problem and everything seems normal now so we will see.

Opinions and comments welcome.

This is a fairly common problem on aging mercedes (many models) and is due to a faulty accelerator pedal/throttle position sensor. As you have sds you were also able to see accompanying code to go with it!

The position sensor is a potentiometer and the repeated pedal action may have cleaned up the contact enough for it to work properly for now, however replacement likely required to prevent repeat occurrence.

Thank you for the very helpful advise. SDS did point right to the pedal sensor. Code P20DD, short circuit at signal path 1 P0123.

I will order a 230 300 01 04 pedal sensor tomorrow and install.

I also show a P20E1 intake air too high but I think that one has been in there for a while and the two are unrelated. Could be a bad cooler pump or air in system. I will check that out later.

could be both

Yes, could be both. Thank you for your input.

The car has two problems for sure. I will correct one at a time.
The great thing about doing the repairs yourself is you can afford to throw parts at it.

I will change the pedal sensor first. The cooler system is on my list of winter projects. Here in Ohio we only have a couple of weeks at best left of cruzn weather.