Symptoms of P0243
- Check-engine light on, sometimes with rough or uneven running.
- Hesitation, surging, or a noticeable change in fuel economy.
- Occasionally hard starting or a smell of unburnt fuel.
Common causes of P0243
- A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
- Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
- Wiring, connector, or fuel-delivery problems that skew the reading.
Useful checks before replacing parts
- Check wastegate solenoid A feed voltage, control command, ground, resistance, connector condition, and circuit continuity under load.
- Inspect vacuum or pressure hoses, actuator movement, wiring near heat, boost leaks, solenoid plumbing, and related boost sensor data.
- Compare wastegate command with desired boost, actual boost, airflow, throttle position, and freeze-frame load conditions.
Related OBD-II codes
These nearby fuel / air entries can help compare wording and pin down the fault area.