[pinoyscorpion951]

Had this happen to me today. Thankfully I was only a half a block away from home. Car went into limp mode. Stayed in 1st gear. Slow acceleration, and I had to manually change the gears from the shift knob to get her home. The neighborhood I live in is on a slight hilly incline. When I got home I turned off the engine, restarted and the reduced engine power notification went away but the CEL light remained on. I proceeded to call onstar to check what the code was and was told it was P2138. Something having to do with throttle position sensor malfunctioning. The car drove fine with the CEL but I immediately took it to the dealer and will leave it overnight. I'll find out more info tomorrow. Anyone else with any experience of this happening? Thanks in advance for the replies.

[SSport16]

Wondering if it has anything to do with the throttle controller? Do you have one of those installed? Just a thought.

[pinoyscorpion951]

Originally Posted by SSport16

Wondering if it has anything to do with the throttle controller? Do you have one of those installed? Just a thought.

That's the first thing I thought of and removed when it happened so yes I do have one. I didn't have a single problem with it on my 5th gen 1LT but I know a few of the L99 and LS3 guys did. It's been completely trouble free in the 2 months I've had it on my 6th gen. If it is in fact the TC, it will be the first issue I've had with it. I may ask Ahmed at Vitesse if I could swap it out with a different one if it is in fact the cause of the CEL. I'll see what the dealer tells me tomorrow. I did remove it prior to sending it in.

[SSport16]

Originally Posted by pinoyscorpion951

That's the first thing I thought of and removed when it happened so yes I do have one. I didn't have a single problem with it on my 5th gen 1LT but I know a few of the L99 and LS3 guys did. It's been completely trouble free in the 2 months I've had it on my 6th gen. If it is in fact the TC, it will be the first issue I've had with it. I may ask Ahmed at Vitesse if I could swap it out with a different one if it is in fact the cause of the CEL. I'll see what the dealer tells me tomorrow. I did remove it prior to sending it in.

Yeah sounds like it could be...keep us posted, hopefully that is all it is, instead of something truly wrong with the car. Good luck!

[BadBillyJack]

DTC P2138
Accelerator Pedal Position (APP) Sensors 1-2 Not Plausible

The ECM detects that APP sensor 1 and APP sensor 2 disagree greater than 10 percent for less than 1 s.

OR

The ECM detects that both APP sensor 1 and APP sensor 2 are 5 percent greater than the learned minimum position for less than 1 s.

Looks to me like it's the throttle controller. You may not want to take that into the dealer and just clear the code yourself.

[jimmypop13]

Yeah dealer will be confused and may try throwing replacement parts at it. It takes a few driving cycles usually for a code to disappear so that's why the light stayed after you removed the controller

[Sledgehammer70]

Haven't had this issue myself, but did have my car go into limp mode on me once, but they said it was due to an undercharged battery and the error codes were simply the ECU not sending the right info. This all happened after the last OnStar update.

[The1DoubleN]

Oh goody......subscribed....since this is on my car for the last 2000mi, no problems yet, fingers crossed nothing goes wrong with it. Keep us posted, good to know if it is indeed the controller for when this happens to someone, they can know to just disconnect it and reconnect the stock connector to the pedal.

Did all of your connections seem secure? Could it have just been a loose connector, or.....if all the connections were tight, like you said, send it to Ahmed so he can open it up and have a look to see if there's an internal connection issue.

I like this throttle controller on my SS, and I know lots of people have used them on lots of cars, but it's stuff like this that worries me, trusting your throttle voltage engineering to a little device that's intercepting the connection between pedal and throttle body....what happens if it shorts? Is it possible the car might accelerate wildly or unpredictably? If so that would really suck mid-corner in the canyons.......

Keep us posted on what the dealer says if they can find a problem with the stock setup. This wouldn't be the first faulty sensor issue on these cars (recall fuel tank sensor fiasco)....could be the car, could be the controller, who knows.....though I guess if the dealer finds no problems and the car drives normally without the controller hooked up, you probably have some kind of answer...

[08z51c6]

Hm , just bought the Vitesse Throttle Controller but haven't installed it yet. Think I'll wait to see how this plays out before I do.

[Glen e]

Just a thought; owners manual says speed limited to 85 when MRC is defective.

[The1DoubleN]

Originally Posted by Glen e

Just a thought; owners manual says speed limited to 85 when MRC is defective.

Speed limited to 85 and Reduced Engine Power are two totally different safe modes, Reduced Engine Power is way more severe....which is what his DIC said.

[The1DoubleN]

I would really love to hear some reassuring words from Vitesse on this thread about how safe these throttle controllers are, and what happens to the car when one stops working or loses power.....

[SSport16]

Originally Posted by The1DoubleN

Oh goody......subscribed....since this is on my car for the last 2000mi, no problems yet, fingers crossed nothing goes wrong with it. Keep us posted, good to know if it is indeed the controller for when this happens to someone, they can know to just disconnect it and reconnect the stock connector to the pedal.

Did all of your connections seem secure? Could it have just been a loose connector, or.....if all the connections were tight, like you said, send it to Ahmed so he can open it up and have a look to see if there's an internal connection issue.

I like this throttle controller on my SS, and I know lots of people have used them on lots of cars, but it's stuff like this that worries me, trusting your throttle voltage engineering to a little device that's intercepting the connection between pedal and throttle body....what happens if it shorts? Is it possible the car might accelerate wildly or unpredictably? If so that would really suck mid-corner in the canyons.......

Keep us posted on what the dealer says if they can find a problem with the stock setup. This wouldn't be the first faulty sensor issue on these cars (recall fuel tank sensor fiasco)....could be the car, could be the controller, who knows.....though I guess if the dealer finds no problems and the car drives normally without the controller hooked up, you probably have some kind of answer...

That is exactly why I stay away from electrical devices like these...ECM's are sensitive to changes like this. Not worth it in my opinion.

[TSloper]

If you want to remap the pedal to throttle relationship do it in the tuning. I certainly wouldn't trust some 3rd party circuit that is certified to absolutely nothing between my foot and the ECM.