Code Definition

P2129 — Accelerator Pedal Position (APP) Sensor Intermittent

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P2129

P2129 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P2129 is stored, the module has detected a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P2129 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

DTC P2129 indicates an intermittent fault in the accelerator pedal position sensor E circuit. The accelerator pedal assembly carries more than one position signal so the control module can cross check driver demand, and the E circuit is the second of these correlated signals. The code sets when the E signal momentarily drops out, spikes, or stops agreeing with its partner signal, rather than failing as a steady open or short. When the module loses confidence in the pedal signals it falls back to a reduced power or failsafe strategy, so the driver may feel sudden hesitation, surging, or a brief...

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