Code Definition

P1120 — Accelerator Pedal Position Sensor Circuit

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Toyota

About P1120

P1120 is a manufacturer-specific powertrain diagnostic trouble code recorded for Toyota vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1120 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.

P1120 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The accelerator pedal position (APP) sensor tells the Engine Control Module (ECM) how far the driver has pressed the accelerator on an electronic throttle control system. Most APP sensors provide two independent voltage signals that track each other at a fixed offset so the ECM can cross check them for plausibility. DTC P1120 is set when the ECM detects an electrical fault in the APP sensor circuit, such as a signal out of range, a loss of the 5V reference, or the two signals failing to agree, caused by an open, a short, or a sensor fault. When this code is set the ECM commonly enters a fail s...

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