Conditions for Setting DTC: P2138
WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The voltage difference between APP sensor 1 and APP sensor 2 exceeds a value of 5 percent with the pedal in the released position, or 10 percent with the pedal at wide open throttle (WOT) for less than 1 second.