What it means
The turbocharger/supercharger bypass valve C is mechanically stuck. Boost recirculation on this branch cannot be commanded.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
A turbocharger or supercharger bypass valve C routes boost air around part of the forced-induction system when commanded. The control module sets this code when valve C does not move as commanded, so boost recirculation on that branch is impaired.
Common causes
Most likely first.
- Bypass valve mechanically seized
- Carbon deposits jam the valve
Symptoms
- Reduced engine power may occur
- Boost response may be affected
How to diagnose it
- Save freeze-frame data and scan related boost-control codes to see when valve C failed to respond and whether the fault is isolated.
- Inspect the bypass valve C, its linkage, and nearby hoses for obstruction, damage, or carbon buildup that could physically jam movement.
- Check the valve connector and wiring for loose pins, corrosion, chafing, or heat damage.
- Use the scan tool's supported actuator test to command valve C and observe whether it moves through its expected range.
- If the valve is free mechanically, test its actuator circuit and control signal against the manufacturer's procedure.
Common fixes
- Remove deposits or debris that are visibly preventing bypass valve C from moving, where the service procedure allows cleaning.
- Repair a loose, corroded, or damaged connector or wire at valve C.
- Replace bypass valve C if it remains mechanically seized or fails the actuator test.
Can I keep driving?
Power may be reduced and boost response may be unpredictable, so avoid hard acceleration, towing, or steep climbs. If the vehicle enters limp mode or power drops sharply, stop somewhere safe and arrange prompt diagnosis.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.