Code Definition

P1128 — Throttle Control Motor Lock Malfunction

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

About P1128

P1128 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.

P1128 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 that the throttle control motor is mechanically stuck or locked, preventing proper throttle valve movement. The ECM monitors the correlation between the commanded throttle position and the actual throttle position reported by the throttle position (TP) sensor. If the motor fails to move the valve as expected despite receiving control signals, the ECM determines a lock condition and stores this fault. When this code is set the vehicle usually enters a fail safe mode with limited or fixed throttle opening, and the driver may notice reduc...

Join TaT to view the complete code information and diagnostic details.

Quick Facts