Jamie_GT3

Hi All,

So I've been scratching my head a little bit. Had this trouble before and we could put a little twist on the wires (putting a bit of side load on the pins in the connector) and we could get it to go away. So we thought that maybe I had messed up one of the receptacles on the harness side of the throttle pedal. Replaced the pins in the throttle pedal harness plug and about 4" of wiring up the harness and the issue remains.

Error: Pedal Potentiometer 1 Implausible.

When I have the cruise control on it will turn off when the event happens and not turn back on.

Throttle plate will only open to about 30% (limp mode), but there is not check engine on the dash.

I did some actual value traces with the durametric and there is nothing obvious about the event, before or after voltages from either potentiometer in the pedal or in the throttle.

Will be taking the car back in for some further diagnosis, but I'm not sure what the shop is going to be able to do...

Any ideas?

Spiffyjiff

sorry if this is a dumb question but your error code def says the word "pedal" right? i had a pot. issue last year in my C2S but the codes all refer to THROTTLE --- P2121, -22, -23, -26, -27, -28 --- so i changed the throttle body first since there are pots in there too (i figured that's where a problem would be - in the engine!) but the issue remained until i simply swapped out the accel pedal. problem solved.

did you try swapping pedal?

(again, sorry if this is redundant but just thought i'd throw in .02)

Jamie_GT3

The error does say pedal. But when I looked it up the OBDII code says throttle/pedal potentiometer. When I get home today I'm going to pull the code again to verify.

It is a new pedal assembly and originally I could put some twists on the cable attaching to the pedal and make the problem go away. This made me and a technician friend believe it was a loose pin.

Since replacing the pins, trouble is still there...

I know the dme is referencing the pedal pot 1 and 2 looking for issues and so far all the traces look ok, but it is just a sample on durametric. May need an o-scope to see the issue...

Jamie_GT3

Did extensive logging with Durametric pro with an Pete Bristow from Bristow's automotive (porsche tech and top notch mechanic) and we didn't find anything in the traces. Pete's going to hook up an o-scope to it. We do believe that the durametric is possibly misleading with the code P0121 as when you look it up on OBDII it's a TPS sensor issue, not a Pedal pot, as durametric calls out...

Hopefully it's as easy as a new throttle...

More to come, it's in the hands of a professional and trusted friend..

Spiffyjiff

Weird issue. May I suggest one more (stupid) place to look? At VIR earlier this year, i was going into limp mode/30% throttle after about 2 laps. it wasnt the same error being thrown as my earlier pot. issue but i do remember the word "throttle" being in an error code (sorry, but do not remember the exact code). and sometimes it wasnt even throwing a code. anyway, thanks to a VERY helpful indy at the track, he literally went straight to the problem - the MAF. the ground wire on the harness to my MAF was backing out. inside the weather pack connector, the catches on the sleeve that hold that ground pin in the MAF were broken, etc. Unbelievable. basically we rigged it to stay in with a wad of tape and no issues the rest of the weekend.

he stated that the MAF is more often than not responsible for ridiclous electrical errors.

FWIW.

Jamie_GT3

Thanks for the help. I'll take a look there as well as the more we dig the more the issue seems centered around the throttlebody... If we can't find it there, we'll check the MAF as well...