P2127 - Accelerator Pedal Position Sensor 2 Circuit Low

[ViperGeorge]

I was at the track with my 15 TA 2.0 on Friday. Coolant temps were high, sometimes hitting 243. I would have to take it easy for a couple of laps for them to come down. Ambient temperature was 77. One lap when the temps were high the car threw P2127 - Accelerator Pedal Position Sensor 2 Circuit Low. I don't think it was related to the temps and it did not clear even after disconnecting the battery. Car runs ok but will not accelerate hard. If you press gas pedal too fast or far the electric throttle symbol lights up in the center of the speedometer (where the shift Stryker light flashes normally).

Car has Arrow PCM and Bellanger headers and exhaust. Front O2 wires are wrapped with 2000 degree shielding and there are DEI exhaust heat shields between pipes and O2s so I think they are ok. All fuses appear good.

Anyone have this problem or seen this code before? If so what was it? I have an appointment with my Viper tech tomorrow but I'd love to have some idea as to what I'm looking at.

[Rapidrezults]

I think you've narrowed it down to either the '15 Arrow PCM programming or the headers and PCM combo. I know of several '14's, including mine, with Arrow PCM and have absolutely no problems to report of after hard track miles. Remember when we were at the Viper experience? We beat the heck out of those cars and they kept asking for more in 90 degree heat. I think one of them was even a '15 model as well. Stock PCMs of course.

[Steve M]

A pedal position code suggests to me that you might need to have a dealer redo the throttle relearn procedure. I'm sure mjorgensen or FLATOUT might have some suggestions as well as to how to proceed.

Do you have an OBD-2 scanner of any sort that would allow you to clear the code in the meantime?

[ViperGeorge]

A pedal position code suggests to me that you might need to have a dealer redo the throttle relearn procedure. I'm sure mjorgensen or FLATOUT might have some suggestions as well as to how to proceed.

Do you have an OBD-2 scanner of any sort that would allow you to clear the code in the meantime?

I could clear the code but I wanted to leave it so the Viper Tech could read it tomorrow. Mark Jorgensen put the Arrow PCM in the car before delivery. Is it possible for the PCM to forget the throttle learn? I had been hoping to take the car to Steamboat for the bucket list event now I'll have to take something else.

[Steve M]

I don't think it can drop the throttle relearn settings...pretty sure that would be stored in non-volatile memory.

Probably not a bad idea to leave the code if you are going to take it in for diagnosis. This might be one of those bad luck things that happen from time-to-time...Gen 4 and 5 Vipers are extremely prone to throwing fits (and codes) for the slightest issues. The drive-by-wire throttle system (which includes the pedal) is very sensitive. This might just be one of those tolerance stacking issues that didn't stack in your favor.

[Jack B]

If you have a scan tool, look for any additional codes, only emission related codes show up in the gauge cluster.

[ViperGeorge]

If you have a scan tool, look for any additional codes, only emission related codes show up in the gauge cluster.

Scanned it and there was another code P2138-Accelerator Pedal Sensor Voltage Correlation

[Jack B]

I would guess, a one time voltage transient or a loose/dirty connector, then again, there are many possibilities

Scanned it and there was another code P2138-Accelerator Pedal Sensor Voltage Correlation

[ViperGeorge]

I would guess, a one time voltage transient or a loose/dirty connector, then again, there are many possibilities

Could be but when you step on the gas the car won't accelerate and a large throttle body thing in red flashes on the speedometer with a message that the accelerator sensor has a low voltage.

[ViperSmith]

http://www.amazon.com/gp/product/B00...ilpage_o01_s00

bought that last week, love it

[Steve M]

I would ask them to reaccomplish the throttle relearn, and go from there. It would probably also be worthwhile to swap the stock PCM back in to see if the problem persists.

[ViperGeorge]

I would ask them to reaccomplish the throttle relearn, and go from there. It would probably also be worthwhile to swap the stock PCM back in to see if the problem persists.

I've given the tech the OEM PCM in case that turns out to be the problem. Mark J. sent me the diagnostics for the code (Thanks Mark), it is like 7 pages long so there is a lot for the tech to check. One possible problem is the PCM, others are wiring and bad sensor.

[Steve M]

I've given the tech the OEM PCM in case that turns out to be the problem. Mark J. sent me the diagnostics for the code (Thanks Mark), it is like 7 pages long so there is a lot for the tech to check. One possible problem is the PCM, others are wiring and bad sensor.

I would guess it has something to do with the latter in this case (wiring or sensor related), but you at least have options to help with the diagnosis.

Either way, let us know what you find.

- - - Updated - - -

That's what I suggested also Steve to at least eliminate a PCM issue first, it will be interesting to see what's happening. The car made it through the 1 Lap event without issue so something recent has happened. I can't for the life of me figure out the temperature issues on the 2.0's though.

How many 2.0s are reporting issues?

[mjorgensen]

I would ask them to reaccomplish the throttle relearn, and go from there. It would probably also be worthwhile to swap the stock PCM back in to see if the problem persists.

That's what I suggested also Steve to at least eliminate a PCM issue first, it will be interesting to see what's happening. The car made it through the 1 Lap event without issue so something recent has happened. I can't for the life of me figure out the temperature issues on the 2.0's though.

[Jack B]

Could the aero be creating a reduced air flow thru the radiator.

That's what I suggested also Steve to at least eliminate a PCM issue first, it will be interesting to see what's happening. The car made it through the 1 Lap event without issue so something recent has happened. I can't for the life of me figure out the temperature issues on the 2.0's though.

[ViperGeorge]

Could the aero be creating a reduced air flow thru the radiator.

I just asked Dick Winkles the same thing.