P0034: Turbocharger/Supercharger Bypass Valve A Control Circuit Low
What to do
Driveable, but go easy on full-throttle use until repaired.
What this code means
The bypass valve control circuit is reading low, typically a short to ground or a failed solenoid winding. Because this valve sits in the pressurised intake tract, check that heat and vibration have not chafed the harness against a charge pipe before replacing the valve.
Likely causes
Start here
- Wiring shorted to ground · moderate
- Failed turbocharger bypass valve · moderate
Less common
- Chafed harness against engine or bracket · moderate
Rare
- Control module driver failure · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P0034.