Code Definition

P1127 — Throttle Control Actuator Power Source Circuit

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

About P1127

P1127 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 P1127 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

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.

P1127 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 loss of power supply to the throttle control actuator, which drives the throttle valve in the electronic throttle control system. The ECM monitors the battery voltage supplied to the actuator, usually through a dedicated relay and fuse, and expects it to remain within a calibrated range. If the voltage is missing, low, or unstable, the ECM logs this fault and typically enters a fail safe mode that limits throttle opening to protect driveability. In this state the driver commonly notices reduced power, a restricted or unresponsive thr...

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