Code Definition

P1129 — Electric Throttle Control System

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

About P1129

P1129 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.

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.

P1129 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 DTC sets when the Engine Control Module (ECM) detects a general malfunction in the Electronic Throttle Control System (ETCS). It typically occurs when the ECM identifies inconsistent or conflicting signals among key ETCS components such as the throttle position sensor (TPS), the accelerator pedal position sensor (APP), or the throttle control motor. The fault is logged when overall system reliability is compromised and the ECM can no longer trust the throttle control loop. This commonly triggers a limp or fail safe mode to protect the engine and drivetrain, with the driver noticing reduce...

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