What causes a P2129 code?

P2129 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a P2129 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2129 active.

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

OBD-II

P2129

Throttle/Pedal Position Sensor/Switch E Circuit High

What it means

Fault occurs when the Engine Control Module detects a voltage signal higher than the specified range on the Accelerator Pedal Position sensor circuit 'E'. This typically indicates a short to voltage or a faulty sensor assembly.