CEL 2138 - APP Sensor Voltage error - No throttle control
 

So I have a problem. I am currently in Ohio, supposed to leave to drive home to RI, pretty much now. I started up my 8 about 15 minutes ago to warm it up, ambient temperature of 2 degrees F. Coldest I have started it.

At first everything was fine, had my AP plugged in watching coolant temps climb. About the time it got to 100 degrees F coolant temp, the idle suddenly picked up to 3,000rpm by itself, and held there. I was standing outside the car at this point, and took a peak at the console, and I had a CEL. Pulled the code, 2138. "P2138 APP sensor No.1/No.2 voltage correlation problem ON 1 CCM "

APP I assume to be "Accelerator Pedal Position". So this strands me until I get it resolved one way or another.

There is only 1 other thread on this, and it seems his was also in the cold, and it somehow resolved itself a few days later.


Any ideas?

Where in Ohio are you now?
That code is generated because the allowed voltage difference between the two APP sensors has exceeded.
First thing I would do is re-seat the connector to the pedal.

Erm, started it back up after letting it sit for about 20 minutes researching this, and CEL cleared, full control of the throttle...

Maybe moisture from condensation from temperature change of warming up the car?

Shrug.

Lets hope it doesn't act up again.
I was going to also suggest, since you have an AP, to view the live data for the APP and see if you get an inconsistent reading while pressing on the pedal.
Oh well... good luck!

Think it was probably moisture and then cold on top of that.
Glad it went away. At anytime during the first start-up did you tap the pedal?
Might have just unstuck it and then on re-start..........another drive cycle(?), it didn't see it so it cleared the code.

Not an unreasonable suggestion there Maz.

I started it up, idle was high (freaking cold after all), had the AP plugged in already, watching coolant come up from 2F, the idle started surging slightly as it tends to do in friggid cold, so I gave a tab bit of throttle to hold the rpm steady at the top of where it was surging to (~2,500rpm), until the coolant temps were up to ~55F, let off, the idle dropped and held steady, got out of the 8 to finish cleaning it off, and glanced in, saw 101F, looked away, and the RPM jumped to 3k and held there.

Hopped in the 8, tried the pedal, no response, noticed I had a CEL and my TCS squiggly car light was on. I pulled the CEL code, coolant was up to 145F so I turned it off, turned it back on, TCS stayed off, CEL was still on, RPM hopped right back to 3k. Turned off, turned key to on, reset the ECU through the AP, CEL did not clear, turned off, turned on, same state still, turned off, left it off, went inside to hunt around here.

20 minutes later went outside to start it up and start pulling more AP data, and it started up and idled where it should have, full throttle control.

:dunno:

Got home fine, no return of issue, started the 8 this morning at 1F, no issue, no throttle control problem.

Gonna grab Zelse's pedal I think, just as a backup in case it happens again and won't return to normal.

Been having the same problem with mine. I'm in Quebec, Canada, and the temperature dropped to around -20 Celsius (-4 F), most likely a lot colder during the night, for the past two days, and I'd lose control of the throttle, rpm steady at 3k.

I can confirm that deep cold triggers this problem since I haven't encountered this problem before, at temperatures ranging from 25C to -10C (we're in a cold spell right now)

I'll try and pull the codes if the problem reappears to confirm if the problem's the same.

Any help / input will be appreciated

Woot! a 3rd person seeing this :)

The 1st posted in 2009, but no mention of it returning.

Does your issue continue to repeat? Does it clear up as the cabin temperature warms up? Does it ever happen AFTER the cabin air temp is warmed up?

I just had it happen the once so far, no repeat. Though typically 2F is a rare event here in RI. Usual low in the winter is around 10F.

1F was yesterday morning, but didn't do it. I'm guessing it is a combination of deep cold and moisture present that freezes, sticking a sensor in 1 position, making the 2 read differently, but it's just a theory. If yours keeps returning, maybe there is moisture stuck in the pedal?

I removed the throttle pedal from another 8 a bit over a week ago, and it's just 2 10mm nuts and a wire connector, nothing else, so maybe bring it inside and let it warm up and air out in dry air?

Just theories and guess work at this point.

This morning was slightly warmer (somewhere close to -11C) and the car started fine, perfect throttle response. Went through it's normal heat up sequence : idles at 3k for a couple of minutes (say 1 or 2).

So far, it happened 3 times, every time was at bone chilling temperatures and a cabin heat up would make the problem go away. (In all occurrences, I had to restart the car, even after it was up to temperature, before getting my throttle back.)

I'd say the condensation / Deep cold theory does make sense, although I don't have the slightest idea how the sensor is hooked up or works.
Is it a 2 part sensor, 1 mobile part on the pedal and a second fixed part on the interior? If there is some sort of contact surface to that sensor, condensation could accumulate on it and block the signal.

I'll try and get some time to look how everything is mounted up, see if I can clean up the sensor if the problem re appears.

The ONLY connections to the car that the pedal has are the 2 bolts in the firewall (nuts on the pedal side), and the electrical connector with wires.

The sensors and everything are totally internal to the pedal.