Damaged, chafed or corroded wiring between the control unit and the bypass valve; Faulty bypass valve solenoid or actuator (open or shorted coil); Poor connection at the valve plug or control unit connector (corrosion, loose or spread pins); Blown fuse, faulty relay or loss of power or ground supply to the valve circuit; Valve seized or sticking mechanically, causing abnormal current draw; Fault inside the control unit output driver.

P00C0

Turbocharger/Supercharger Bypass Valve B Control Circuit.

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
C0: FaultThe specific fault in that area

What it means

P00C0 means the engine control unit has found an electrical fault in the control circuit of turbocharger or supercharger bypass valve B. It sets when the commanded state of the valve driver does not match the voltage or current the unit measures, which points to an open circuit, a short or a failed valve. Which valve is 'B' (for example a second turbo stage, a bank or a recirculation valve) depends on the model and engine.

Symptoms

Engine warning light on
Reduced power or limp mode
Poor or inconsistent boost pressure
Hesitation or turbo lag on acceleration
Whistling, fluttering or hissing from the intake during lift-off or acceleration
Rough or unstable response when the throttle is applied or released

Possible causes

Damaged, chafed or corroded wiring between the control unit and the bypass valvelikely
Faulty bypass valve solenoid or actuator (open or shorted coil)likely
Poor connection at the valve plug or control unit connector (corrosion, loose or spread pins)possible
Blown fuse, faulty relay or loss of power or ground supply to the valve circuitpossible
Valve seized or sticking mechanically, causing abnormal current drawpossible
Fault inside the control unit output driverrare

How to diagnose

Read all stored and pending codes and note the freeze frame data (engine speed, load, battery voltage) to see when the fault set.
Check for other boost, turbo or supply voltage codes that could point to a shared cause.
Visually inspect the wiring and connector at the bypass valve valve B, looking for heat damage, chafing, oil contamination and corrosion.
Check the fuse and relay for the valve circuit and confirm battery voltage is healthy.
With the ignition on, check the supply voltage and ground at the valve connector against the manufacturer's wiring diagram.
Measure the valve solenoid resistance and compare with the manufacturer's specification for that engine.
Use the scan tool's output test, if available, to command the valve and check that it moves, clicks or responds.
Check the valve for free movement, and any vacuum or pressure lines if it is not purely electric, then check the control unit for a relevant calibration update as given by the manufacturer.

How to fix

Repair or replace damaged wiring, and secure it clear of heat and moving parts.
Clean or replace the corroded or damaged connector terminals.
Replace the faulty bypass valve or its actuator.
Replace the faulty fuse or relay after finding why it failed.
Free or replace a sticking valve and fix any oil or carbon contamination causing it.
Replace or repair the control unit only after wiring and valve have been proven good.

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, often in limp mode with reduced power, but get it fixed soon. Uncontrolled boost or a stuck valve can stress the turbo and engine, so avoid heavy throttle until it is repaired.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.