Code
P00C2
Generic
P — Powertrain
Turbocharger/Supercharger Bypass Valve B Control Circuit High
Views:
UK: 18
EN: 43
RU: 24
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring in the bypass valve B control circuit
- Short to battery (high voltage) on the control wire
- Corroded, loose, or damaged connector at the valve or PCM
- Failed bypass valve solenoid/actuator (internal short or internal fault)
- Poor or missing ground reference
- Faulty PCM/ECM output driver
Symptoms
- Check Engine MIL illuminated (DTC P00C2 stored)
- Poor or erratic boost control; turbo/supercharger performance reduced or inconsistent
- Engine enters limp mode or reduced power mode under some conditions
- Hissing from bypass/diverter valve or unusual boost leaks detected
- Reduced fuel economy or hesitation on acceleration
What to check
- Confirm DTC P00C2 and note freeze frame / live data from a scan tool
- Visual inspection of the bypass valve B connector, wiring harness, and PCM connector for damage or corrosion
- Check for aftermarket modifications or recent repairs that may have disturbed wiring
- Backprobe the valve connector and measure voltage with key ON / engine OFF, and during commanded operation using a scan tool
- Measure coil/solenoid resistance at the valve (engine off, harness disconnected)
- Check continuity and insulation between the control wire and battery/ground to identify shorts/opens
Signal parameters
- Supply battery voltage to circuit: ~11–14.5 V with engine running (vehicle-specific)
- Control signal: many systems use a PWM output from the PCM — duty cycle varies 0–100% (frequency commonly 20–300 Hz; vehicle-specific)
- Expected 'low' voltage on control wire when active: ~0–1 V (if PCM is switching to ground); expected 'high' when off: near battery voltage (~11–14 V) — consult vehicle wiring diagram
- Typical solenoid coil resistance range: ~5–50 ohms (varies by manufacturer; measure and compare to spec)
- A true 'circuit high' fault means measured voltage on the control circuit is higher than the PCM expects for the commanded state (possible short to battery)
Diagnostic algorithm
- Retrieve freeze frame and any related turbo/boost DTCs. Clear codes and attempt to re-create the fault to confirm it is current and to capture live data.
- Perform a careful visual inspection of the bypass valve B connector, wiring harness, and PCM connector for damaged insulation, pin corrosion, bent pins, or signs of heat/abrasion.
- With ignition ON (engine OFF), backprobe the control wire at the valve connector. Verify and record the voltage with the PCM commanding the valve ON and OFF (use a scan tool to command if possible). Compare to expected behaviour.
- Disconnect the valve harness and measure the solenoid coil resistance with a multimeter. Compare resistance to the vehicle specification. An open or very low resistance may indicate a faulty solenoid.
- Check for shorts: measure continuity between the control wire and constant battery (short-to-battery) and to chassis ground (short-to-ground). Repair any short circuits found.
- If wiring and solenoid check good, perform a harness continuity check between the valve connector and PCM connector for opens or high resistance. Repair any wiring faults.
- If the circuit shows high voltage only when connected to the PCM (and wiring/solenoid are good), suspect a PCM output driver fault. Verify by swapping with a known-good channel (if identical and documented safe) or consult manufacturer diagnostics before replacing PCM.
- After repairs, clear codes, road test and monitor live data for boost/bypass valve operation to ensure the fault does not return.
- Replace the bypass valve solenoid/actuator and/or repair wiring/connectors as required. Replace PCM only after all other components and wiring are confirmed good.
Likely causes
- Damaged harness or connector causing a short to battery on the control circuit
- Failed bypass valve solenoid with internal short or open
- Contaminated/corroded connector causing high resistance and abnormal voltage
- PCM output driver failure (less common) after wiring and valve checks
Fault status
Status
PCM detected a high voltage condition on the Turbocharger/Supercharger B bypass valve control circuit (circuit voltage higher than expected). Possible wiring short to battery, connector fault, solenoid failure, or PCM driver issue.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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