tfkrato

2008 MN6 785 miles. Was about 1.5 miles into a drive yesterday and was at about 20 MPH when I gave it 1/2-3/4 throttle on a dry straight road. Car barely started to accelerate when within seconds it bogs down. CEL and Traction Control lights come on and DIC messages "REDUCED ENGINE POWER" and "SERVICE TRACTION SYSTEM" come on. Drive it back home and retart it and the DIC messages are gone but CEL and Traction Control lights are on. Called Onstar and they said you may be able to restart and things return to normal. They then ran diagnostics and car has code P2138 (which I find later is "Accelerator Pedal Position (APP) Sensor 1-2 Correlation ECM"). Onstar says it needs to be taken in for service. I do a couple restarts and Traction Control light clears but CEL stays on. I read on forum that holding Options button while pressing Mileage button 4 times clears CEL. It did not. After a couple more restarts the CEL clears.

I drive the car about a mile, turn a corner, give it maybe 1/4 throttle and same lights (CEL & TC) and DIC messages appear. After a couple restarts DIC messages are still on along with CEL & TC. I park it for the night.

This morning needed to run a 5 mile errand. CEL still on but not TC light or DIC messages. The car runs beautifully. Accelerates fine.

I check the car in the late afternoon and when I start it the CEL is not off. Everything looks normal. I take it for a 5 mile drive with several spirited accelerations. Car again runs superbly with no issue.

Now debating on whether to update the dealer I spoke to the day first day or drop it off with them to check it out.

Any thoughts?

Hawk07

Take it in and let them read the stored codes. Sounds like something on it's way to going bad. No need to get left high and dry somewhere when you could have taken it and had the offending part replaced.
No reason to keep "waiting" for it to happen again.

FortMorganAl

P2128 Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage ECM

You have an intermittent problem with the #2 accelerator pedal position sensor. It needs to be replaced and/or the wiring checked. As much as I would prefer a root canal appointment over going to a dealer for anything, take it to the dealer.

VET4LES

You need to take it in. That's what the warranty is for. Good luck.

maxp

sorry to hear about this. Let me know how the service goes at AS, I am thinking about using them instead of Champion when I need service.

dvilin

talon90

First and foremost, the trick of holding the option button and pressing the mileage button 4 times was from the C5. This would allow you to get in to the diagnostic mode via the DIC. The C6 does not have this feature.

If it is in fact your accelerator position sensor it will happen again. You will be better off taking it in to the dealer and having them take a look at it. If it fails all together you may be left stranded. The C6 is not a standard "accelerator cable on pedal pulls lever someplace else" car. The C6 uses more of a "fly by wire" system like that in modern military aircraft. If the position sensor fails completely you may not be able to move.

tfkrato

I took the car to the dealer and they could not recreate the problem (no surprise). They called the Vette engineer and he advised to check all the connections associated with the accelerator. The Mechanic said there was a little movement when he checked the connection at the accelerator pedal. He said it seem to seat more fully. There was nothing else they could do since everything was working fine. I haven't driven it much since then (it's only been 2 more day since the at the dealer), but it has driven flawlessly. Really hope this is solved. I told the dealer this could be really dangerous if I'm in a passing situation and the car suddnely decelerates and throws DIC messages.