Engine and gearbox (P)
P0033: Turbocharger Bypass Valve Circuit Fault
The engine control unit (ECU) has detected an electrical issue in the turbocharger bypass valve control circuit. This means the voltage or current in the solenoid is not what it should be when the ECU tries to control it.
Checked by a licensed car technician · last reviewed 29 September 2026
Symptoms
- Reduced engine power
- Check engine light on
- Poor acceleration
- Possible hissing noise from engine
Common causes
- Bypass solenoid failed
- Open or shorted wiring to solenoid
- Connector corrosion or poor contact
How to check it yourself
- Inspect and clean solenoid connector
- Check wiring for damage or disconnection
- Test solenoid for proper operation
- Use a multimeter to check circuit continuity
Can I keep driving?
The car can still be driven, but performance may be reduced.
General guidance, not a professional inspection. Confirm faults with measurements before buying parts, and use a qualified mechanic for brakes, steering, fuel leaks, airbags, and other safety-critical work. Terms and disclaimer