The other day, my wife told me there was something wrong with her car (2012 Chevy Malibu). The “Check Engine” light was on, the odometer area was reading"engine power reduced", “service ESC” , and “service traction control.” The only error code was P2138, a throttle-by-wire error.
There was water on the headliner and floor, and the storage bin on the dash next to the driver’s door was completely full of water.
Fearing the worst, I made an appointment with my mechanic. But I also did some searching on the Interwebs. Sure enough, there lay the solution:
The drainage tube for the sunroof had become disconnected up at the sunroof, channeling water down the inside of the A pillar trim, directly onto a large electrical connector on the far left of the dash. Reconnecting the tube (and securing it with Gorilla Tape), drying everything out, and clearing the error code and, wonder of wonders, everything is back to normal!
I love a happy (and essentially free) ending, but I am posting this for another reason also. Apparently, this problem affects a multitude of GM vehicles, and the error code and fix are the same for all of them.