Turbo Charger Bypass Valve Control Circuit High
Diagnostic trouble code P0035 indicates that the engine control module (ECM) has detected an unexpectedly high electrical voltage in the turbocharger bypass valve control circuit. This typically points to an open circuit, a short to power, or a failed bypass valve solenoid preventing proper boost pressure regulation.
While the vehicle can usually still be driven, driving with this code can lead to poor performance and potential turbocharger damage over time due to compressor surge. It should be diagnosed and repaired soon to restore proper engine operation.
Common symptoms
- Illuminated Check Engine Light
- Noticeable lack of engine power or poor acceleration
- Abnormal turbocharger noises, such as fluttering or surging when lifting off the throttle
- Engine hesitation or stumbling during deceleration
- Vehicle entering a reduced power or 'limp' mode
Likely causes
- Faulty turbocharger bypass valve solenoid
- Corroded, damaged, or loose electrical connector at the bypass valve
- Open or short-to-voltage wiring in the bypass valve control circuit
- Damaged or disconnected vacuum lines associated with the bypass valve system
- A failing engine control module (ECM) (rare)
What to check before replacing parts
Visually inspect the wiring harness and connector at the turbo bypass valve.
Look for: Look for frayed wires, melted insulation, corrosion on the pins, or a disconnected plug that would cause an open circuit.
Test the resistance of the turbo bypass valve solenoid using a multimeter.
Look for: Compare the measured ohms to the manufacturer's specification; an infinite reading (OL) indicates an internal open circuit in the solenoid.
Check for proper voltage and ground at the bypass valve connector with the ignition on.
Look for: A lack of voltage or ground indicates a wiring issue between the ECM and the valve, or a short to power if voltage is present on the ground circuit.
Use a bi-directional scan tool to command the bypass valve on and off.
Look for: Listen for a clicking sound from the valve; if it does not click despite having good power and ground, the valve is mechanically stuck or internally failed.
Inspect the mechanical bypass valve and associated vacuum lines (if the solenoid controls vacuum).
Look for: Look for cracked, collapsed, or disconnected vacuum hoses, or a torn diaphragm in the bypass valve that prevents it from actuating properly.
This page explains the generic P0035 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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