The P1125 code in your 2020 Toyota Yaris indicates a malfunction in the throttle control motor circuit. This Toyota-specific code signals issues with the electronic throttle body that controls engine airflow in drive-by-wire systems.
Electronic Throttle Control
The Yaris uses electronic throttle control (no cable to the throttle body). The accelerator pedal sends a signal, and the throttle motor opens the butterfly valve. P1125 indicates a problem with the motor or its circuit.
Common Causes of P1125
- Throttle motor failure
- Throttle body contamination
- Wiring damage to throttle body
- Connector corrosion
- ECU driver circuit failure
- Throttle position sensor issues
Symptoms of Throttle Motor Issues
- Check engine light on
- Reduced power mode (limp mode)
- Poor throttle response
- Engine won't rev properly
- Idle speed problems
- Vehicle may not accelerate
Safety Implications
Electronic throttle issues are safety-critical. The Yaris has multiple failsafes, including limp mode that limits power when problems are detected.