Eric Perry

I was driving home from work last night, and all of a sudden, my TL throws CEL, VSA, and Exclamation Point lights. I didn't notice any changes in performance initially as I was cruising at 45 MPH or so on a flat road. When I tried to step on it, there was a whole bunch of nothing there. I was reluctant to shut it off and restart, fearing the worst, so limped home. Sure enough, it fell into limp mode. When I restarted, the Exclamation Point and VSA lights were gone, but the CEL remained. I pulled codes and got a "P2138 - Throttle/Pedal Position Sens/ Sw D/E Volt Correlation" code. I cleared to codes and drove my 25 minutes or so to work this AM with no issues at all.

I I checked the cable this AM for excessive play, and there was none. I don't feel like simply waiting to throw more P2138 codes and falling back into Limp Mode, so I went ahead and ordered the APP Sensor today. $143 delivered. Hopefully it'll be here quick and I can fix it for good!

Thanks to the forum for your help in pretty quickly diagnosing / verifying the issue!

nfnsquared

The APP sensor is really two identical sensors that both send voltage signals (based on pedal position) to the ECU. The ECU compares the two voltage signals and if they are equal, everything is OK and the ECU sends the appropriate signals/codes for acceleration/deceleration.

When the voltages don't match, then it throws a CEL and puts you into limp mode. The double sensor prevents runaway throttle situations (ala Toyota).

It may very well be that one of the two sensors is going bad or it could have been a spurious situation. Hard to know, but based on what I've seen of APP sensor failures, it probably is a bad sensor.

roof2006

When my car did that same thing, it was the app sensor. My mechanic was able to test the sensor first once I suggested that he look for it.

Eric Perry

Mine just arrived yesterday. I'll be installing it later today...

daveydryden

How many miles did you have on it when this happened?

Eric Perry

About 64k plus change.

MistahWes06TL

I think i might have this issue also. While i was driving in cruise control on te highway, i hit a small dip, and after that cruise control shut off and the car jerked forward for a second. The car drove fine after that, but when it jerked forward it popped a CEL. Im trying to get my hands on a code reader to figure out what the CEL light is on for. Does this sound like it would be the same thing though? Ive never had to deal with anything like this before.

Eric Perry

Without pulling the codes, it's too hard to say. It could be countless different things. Honestly, based on my experience, it's not the APP though. Mine tripped the CEL, VAS, and traction control lights, *and* went into limp mode. Check the CEL codes and let us know. As far as I know, Autozone and Advance Auto will pull them for free.