Code Definition

P2120 — Throttle/pedal position sensor 4 circuit/open

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

About P2120

P2120 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 P2120 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit; and 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 P2120 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

Throttle or pedal position sensor 4 is one of the signal tracks within the accelerator pedal position assembly that the engine control module uses to interpret driver demand for the electronic throttle system. DTC P2120 sets when the ECM detects an open circuit or a voltage outside the expected range on this sensor 4 circuit, meaning the signal is missing, erratic, or does not correlate with the other pedal position sensors. Because the ECM relies on agreement between the pedal signals for safety, a fault on this circuit usually forces a reduced power or limp mode. When the code is set the dri...

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