Code Definition

P1120 — Throttle motor position sensor 1 circuit fault

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

About P1120

P1120 is a manufacturer-specific powertrain diagnostic trouble code recorded for Isuzu 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

This Isuzu DTC sets when the Engine Control Module (ECM) detects an out of range, missing, or erratic signal from Throttle Motor Position Sensor 1, part of the electronic throttle control system. This sensor monitors the position of the throttle plate and feeds a voltage signal to the ECM, serving as the primary input while a second sensor provides redundancy. The code logs when sensor 1 deviates from its expected voltage range or disagrees with the companion sensor under matching throttle conditions. Because the ECM can no longer trust the throttle position, it commonly triggers a warning lig...

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