What it means
Generic electrical fault on bypass valve B control. Same family as P0039 on actuator B. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bypass valve B is part of a turbocharger or supercharger system and controls airflow around the compressor when the system needs to regulate boost. The control module monitors the electrical control circuit for valve B. P00C0 sets when that circuit has a fault, without specifying the low-voltage or high-voltage condition named by related codes.
Common causes
Most likely first.
- Bypass valve B solenoid or actuator failed
- Open or shorted control wiring
- Loose or corroded connector
- Bypass valve stuck or obstructed
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
How to diagnose it
- Read freeze-frame data and related boost-control codes to see when the valve B circuit fault occurred and whether boost symptoms were present.
- Locate bypass valve B using vehicle service information and inspect its connector, wiring, and nearby hoses for disconnection, damage, or obstruction.
- Check that the valve and its linkage or actuator move freely where visible, without forcing the mechanism.
- Use a scan tool's actuator command, if supported, to compare the commanded response with valve B's observed operation.
- Test valve B's control circuit and actuator using the manufacturer's specification to distinguish wiring faults from a failed valve.
Common fixes
- Reconnect or secure a loose valve B electrical connector or boost hose.
- Repair damaged or corroded wiring in the valve B control circuit.
- Remove an obstruction or repair a bypass valve B mechanism that is sticking.
- Replace the bypass valve B solenoid or actuator if circuit and operation tests confirm failure.
Can I keep driving?
If the vehicle drives normally, use light throttle and avoid sustained high boost until the fault is diagnosed. Stop if power becomes unpredictable or the engine makes unusual forced-induction noises, since boost control may be impaired.
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.