Thread: Need Help Before Wife Kills Me!!!

Wife is ready to kill me! Wants her car back. Need help troubleshooting the following codes.
I've got an '06 Grand Prix GT, 3800 w/SC. I get two fault codes. P1125 Throttle Position/Accelerator Pedal Position Sensor Ckt Problem. And, P2138 Accelerator Pedal Position Sensor 1-2 Correlation. The problem is intermittent and is accompanied by the Check Engine Light and an information center alarm "Reduced Engine Power" and then the car runs really rough at idle. I conclude from these two fault codes that the comparison of the postition of the gas pedal and the position of the throttle are in some sort of disagreement and the computer is flaging it. I'm assuming a lot when it comes to troubleshooting cars on fault codes alone, so whomever reads this please bear with me as I make educated guesses. I'm assuming that the electronic throttle control system works as follows and please correct me if I'm wrong. The gas pedal has a potentiometer built in to it and the signal is transmitted to the throttle positioning unit on the throttle body and the servo motor would then drive the throttle into the appropriate postion. Question is......do I replace the gas pedal assy and if that doesn't fix it replace the throttle assy? Or, is there something else wrong with the thing?

Any help is appreciated.

Thanks!

Clean your throttle body.

Think it's sticking? Thanks, I didn't think about the obvious, duh on me! I'll give it a try and will let you know.

Thanks!

Appreciate the response everyone! Tried cleaning the throttle up, it was dirty, but still have the same problem. I'm assuming the TPS is the least expensive to replace, so will try that next. It was so much easier when cars were built more simple and had carburetors with a direct link to the throttle and not all this computerized junk.

Thanks again for the input and will keep ya'll posted.

No Mods. It happens intermittently, after you lift your foot off the gas and are coasting, any speed.

I've done a little more homework. First, the '06 model uses a 'fly-by-wire' electronic throttle control. The TPS is part of the assembly at the throttle body. The other end is the Accelerator Pedal Assembly. So I started looking online for replacement parts. I tried Pep Boys, Autozone and Kragen/O'Reilly. None of these stores had either part listed, so I figured it will be a dealer item only situation. Then I remembered Napa Auto Parts. Back in the day when I wrenched for a living, these guys seemed to have parts that nobody else had. So I went online and sure enough, they had this listing under Sensors. Accelerator Pedal Position Sensor. $51.99 When you look at the pictures of the part, it's the gas pedal assy. My failure codes seem to point directly to this part and if true, my hat is off to GM for making something that actually troubleshoots itself to the correct part. P1125 Throttle Position/Accelerator Pedal Position Sensor Circuit Problem. And, P2138 Accelerator Pedal Position Sensor 1-2 Correlation. Hey, for $51.99 it's worth it to find out! Also, why would Napa carry this part? Maybe a higher than usual failure item. It would make sense too, if the gas pedal assy uses a potentiometer, it would eventually wear out. We will see what this replacement does later this month when I have the time to work on it again.

Jakegday, loved the response, still laughing while typing. Well, when I called NAPA to inquire about part availability for the Accelerator Pedal Position Sensor (accelerator pedal assy), it turned out that they didn't have any nation wide. So, went to Pontiac and they found me one at a local Chevy dealer. $48.00 or so out the door. Took about 5 mins to install. Car runs great. Still find it hard to believe that they finally made a car computer that can isolate to a particular part, or at least this particular part instead of some cryptic message.
Thanks to all for the responses!! Now I get to find out why the right front axle that I just replaced is slinging grease from the CV boot, what a mess.

Cheers!
SubWarrior632