Code Definition

P0120 — Throttle Pedal Position Sensor / Switch A Circuit

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

About P0120

P0120 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 P0120 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 P0120 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

The throttle and pedal position sensor A circuit reports driver demand and throttle plate position to the ECM on electronic throttle control systems. Depending on the vehicle, sensor A may sit at the accelerator pedal assembly, at the throttle body, or at both, with most systems using two independent sensors at each location so the ECM can cross check one against the other for plausibility. P0120 sets when the ECM detects the sensor A signal outside its acceptable operating range, a definition covering open circuits, shorts, and signals that fail the plausibility comparison against the partner...

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