P0033 – Turbocharger/Supercharger Bypass Valve Control Circuit
The P0033 diagnostic trouble code (DTC) indicates that the Engine Control Module (ECM) has detected a malfunction in the turbocharger or supercharger bypass valve control circuit. The bypass valve, also known as the diverter valve or blow-off valve on some vehicles, regulates boost pressure by releasing excess compressed air when needed to protect the turbocharger and improve engine performance.
Symptoms of P0033
- Check Engine Light illuminated.
- Reduced engine power.
- Loss of turbo boost.
- Poor acceleration.
- Engine may enter limp mode.
- Whistling or unusual turbocharger noises.
- Increased fuel consumption.
Common Causes
- Faulty turbocharger bypass valve (diverter valve).
- Open or shorted control circuit.
- Damaged wiring or loose electrical connectors.
- Vacuum hose leak (on vacuum-operated systems).
- Faulty boost pressure control solenoid.
- ECM malfunction (rare).
How to Diagnose P0033
- Scan for additional diagnostic trouble codes.
- Inspect the bypass valve and electrical connector.
- Check the wiring harness for damage or corrosion.
- Inspect all vacuum hoses for leaks or disconnections.
- Test the bypass valve and boost control solenoid.
- Verify proper turbocharger boost pressure using a scan tool.
Possible Repairs
- Replace the faulty bypass (diverter) valve.
- Repair damaged wiring or connectors.
- Replace leaking or damaged vacuum hoses.
- Replace the boost pressure control solenoid.
- Repair or replace damaged turbocharger components if necessary.
Can You Drive With Code P0033?
The vehicle can usually still be driven, but performance may be significantly reduced. Driving for an extended period with this code may increase turbocharger wear and reduce engine efficiency, so repairs should be made as soon as possible.
Estimated Repair Cost
- Bypass valve replacement: $100–$400
- Vacuum hose repair: $20–$100
- Boost control solenoid replacement: $80–$300
- Wiring repair: $50–$200
- Turbocharger replacement (if required): $800–$3,000
Related Trouble Codes
- P0034 – Turbocharger/Supercharger Bypass Valve Control Circuit Low
- P0035 – Turbocharger/Supercharger Bypass Valve Control Circuit High
- P0234 – Engine Overboost Condition
- P0299 – Turbocharger Underboost Condition
- P2261 – Turbocharger Bypass Valve Mechanical Performance