Short to voltage in the bypass valve B control wiring; Faulty bypass valve solenoid or actuator with an internal electrical fault; Damaged, corroded or loose connector terminals at the valve or control unit; Open circuit on the valve return (earth) side, causing a high voltage reading; Chafed harness near hot turbo or exhaust components touching a live supply; Fault inside the engine control unit driver circuit.

P00C2

Turbocharger/Supercharger Bypass Valve B Control Circuit High.

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
C2: FaultThe specific fault in that area

What it means

P00C2 is a generic code meaning the control unit has detected a high voltage or short to voltage fault in the control circuit for turbocharger or supercharger bypass valve B. The engine control unit commands the valve and monitors the circuit, and it saw a voltage higher than expected for the commanded state. Which valve is 'B' and how it is arranged depends on the model and engine, for example a twin-turbo or compound setup.

Symptoms

Engine warning light on
Reduced power or the engine going into limp mode
Poor or uneven boost response
Hissing or whistling from the intake, or turbo flutter on lifting off the throttle
Hesitation under acceleration
Possible rough running or reduced fuel economy

Possible causes

Short to voltage in the bypass valve B control wiringlikely
Faulty bypass valve solenoid or actuator with an internal electrical faultlikely
Damaged, corroded or loose connector terminals at the valve or control unitpossible
Open circuit on the valve return (earth) side, causing a high voltage readingpossible
Chafed harness near hot turbo or exhaust components touching a live supplypossible
Fault inside the engine control unit driver circuitrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine load, speed and battery voltage
Check for related codes such as boost pressure, turbo control or other circuit faults, and fix any supply or earth faults first
Visually inspect the bypass valve B, its connector and harness for heat damage, chafing, oil contamination and corrosion
Disconnect the connector and check the terminals for bent, pushed-back or corroded pins
Using the manufacturer wiring diagram, test the control wire for a short to voltage, and check the supply and earth continuity
Measure the valve solenoid resistance and compare it with the specification for that model
Use a scan tool with bidirectional controls, if supported, to command the valve and check that it moves and the circuit voltage changes
Only if the wiring and valve test fine, check the control unit driver output and look for any applicable software update

How to fix

Repair or replace any damaged wiring that is shorted to voltage, and secure it away from heat
Replace the bypass valve or its solenoid if the resistance or operation is out of specification
Clean or replace corroded or damaged connector terminals and the connector housing
Repair any open circuit on the earth or return wire
Replace or repair the engine control unit only after all wiring and the valve are confirmed good, and apply an updated calibration only if the manufacturer lists it as a known fix

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but it may have limited power and the fault could worsen or stress the turbo. Get it checked soon, and avoid heavy loads or hard acceleration until it is fixed.

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