P00C3
Turbocharger/Supercharger Bypass Valve B Control Circuit Range/Performance.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 0
- AreaFuel and air metering, auxiliary emission controls
- C3
- FaultThe specific fault in that area
What it means
P00C3 means the engine control unit has found a range or performance problem with the control circuit for turbocharger or supercharger bypass valve 'B'. The valve's commanded state and its actual response, feedback or circuit behaviour did not agree, or the circuit stayed outside the expected range. Which valve is 'B' depends on the engine layout, so check the model-specific information.
Symptoms
- Engine warning light on
- Loss of power or reduced boost, possibly with the engine in limp mode
- Hissing, fluttering or whooshing from the intake when lifting off the throttle
- Hesitation or surging under boost
- Poor throttle response or turbo lag
- Possible increase in fuel consumption
Possible causes
- Bypass valve (recirculation or diverter valve) sticking, worn or leaking, or its diaphragm or actuator failinglikely
- Wiring or connector faults in the valve control circuit, such as chafing, corrosion, high resistance or a loose pinlikely
- Vacuum or pressure supply problem to a pneumatically operated valve, such as a split hose, leak or faulty control solenoidpossible
- Boost leak or restriction in the intake or charge-air path that makes the valve appear not to respond as commandedpossible
- Faulty position feedback sensor, if the valve is electrically actuated and has onepossible
- Engine control unit fault or outdated calibration, where a manufacturer update is known to address thisrare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting load, engine speed and boost at the time the code set. Check for related boost, turbo or wastegate codes.
- Check for technical service bulletins or known issues for this make, model and engine, and confirm which valve is 'B' on this layout.
- Visually inspect the valve, its connector, wiring and any vacuum or pressure hoses for damage, chafing, oil contamination, cracks or looseness.
- Inspect the charge-air pipes, clamps and intercooler for leaks or oil residue, and pressure test the intake system if the procedure allows.
- Check the valve moves freely and fully by hand or through a scan tool actuator test, and check it holds position without leaking.
- Test the control circuit supply, earth, signal and resistance against the manufacturer's wiring data, and check any feedback signal if fitted.
- Check the vacuum or pressure supply and control solenoid operation for pneumatically operated valves.
- After repair, clear the code and road test while monitoring commanded against actual valve and boost values.
How to fix
- Replace the bypass valve or its actuator or diaphragm if it is sticking, leaking or failing the function test.
- Repair or replace damaged wiring, terminals or connectors in the control circuit.
- Replace split or perished vacuum or pressure hoses and a faulty control solenoid.
- Repair any boost leaks or intake restrictions found in the charge-air system.
- Replace a faulty valve position sensor where fitted.
- Update the engine control unit software only if the manufacturer lists it as a fix for this fault.
Can I keep driving?
The car can usually be driven carefully for a short time, but expect reduced power and possible limp mode. Get it checked soon, as a failing bypass valve can put extra stress on the turbocharger or supercharger.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.