HELP!!!! P2138, C0242 reading

James Dixon · June 12, 2018

I’m at my wits end over this

I’m not sure if it’s been discussed on here yet but I’m having a serious problem with my truck going into limp mode at random.

I have a 2007 GMC Sierra, SLT, Z71 (newer body style)

It runs fine for weeks, sometimes even months. Out of nowhere it’ll go into limp mode with these dash warnings:

”engine power reduced”

”traction control off”

”service traction control”

”service stabilitrack”

Readings are:

P2138

C0242

C0899

C0900

I replaced the engine due to a cam and lifter problem about 3 yrs ago. The truck started acting up about a month after the engine was replaced. The engine is still under warranty.

-I’ve changed the gas pedal sensor.

-I’ve changed the throttle body and throttle positioning sensor.

-I’ve changed the electronic control module (ECM)

-I’ve changed the electronic brake control module (EBCM)

-I’ve even replaced the battery cables

-I’ve added a new ground wire, thinking I had a bad ground somewhere.

- I’ve checked and cleaned all connections into the throttle body, gas pedal, and all the plug ins I could see and get to.

I had a guy tell me to look at the brake booster and possibly change that. It might be leaking or something. I’m not sure if that’s accurate advice and I haven’t done anything to the brake booster.

Other than fooling with the brake booster, I’ve literally done everything I know to do except change the entire wiring harness!!! I don’t want to do that though. I love the truck and I don’t want to sell it but Im tired of putting money into it.

Any help would be greatly appreciated. I’m on the verge of pushing it off of a tall cliff!

help!

- James