P0039 Code – Turbocharger/Supercharger Bypass Valve Control Circuit Range/Performance
P0039 is an OBD-II diagnostic trouble code that indicates the Engine Control Module (ECM) has detected that the turbocharger or supercharger bypass valve control circuit is operating outside the expected range or is not performing correctly.
Code Meaning
P0039 – Turbocharger/Supercharger Bypass Valve Control Circuit Range/Performance
Symptoms
- Check Engine Light illuminated.
- Reduced engine power.
- Poor acceleration.
- Loss of turbo boost pressure.
- Increased fuel consumption.
- Possible limp mode on some vehicles.
Possible Causes
- Faulty turbocharger bypass (diverter) valve.
- Damaged or disconnected vacuum hose.
- Open or shorted bypass valve wiring.
- Poor electrical connector.
- Boost leak in the intake system.
- Faulty ECM (rare).
Component Location
The bypass valve is mounted on or near the turbocharger or supercharger and controls boost pressure by diverting compressed air when required.
How to Diagnose
- Confirm P0039 with an OBD-II scanner.
- Inspect the bypass valve and vacuum hoses.
- Check the electrical connector and wiring.
- Test the valve operation using a scan tool or vacuum pump (if applicable).
- Inspect the intake system for boost leaks.
- Replace the valve if it fails functional testing.
Common Repairs
- Replace the bypass valve.
- Repair damaged wiring or connectors.
- Replace cracked or leaking vacuum hoses.
- Repair boost leaks in the intake system.
- Clear the code and perform a road test.
Can You Drive with P0039?
Yes, but the vehicle may have significantly reduced performance and poor boost control. The problem should be repaired promptly to prevent further turbocharger-related issues.
Related OBD-II Codes
- P0033 – Turbocharger/Supercharger Bypass Valve Control Circuit
- P0034 – Turbocharger/Supercharger Bypass Valve Control Circuit Low
- P0035 – Turbocharger/Supercharger Bypass Valve Control Circuit High
- P0234 – Engine Overboost Condition
- P0299 – Turbocharger Underboost Condition