Faulty bypass (recirculation or blow-off) valve or its solenoid with an internal electrical fault; Wiring fault such as a short to voltage, chafed insulation or damaged harness near the valve; Corroded, loose or damaged connector at the valve or control unit; Blown fuse or a fault in the power supply feeding the valve circuit; Valve mechanically stuck or damaged, causing abnormal circuit readings; Faulty driver circuit inside the engine control unit; Outdated control unit software where the manufacturer has issued a known fix for the model.

P0035

Turbocharger/Supercharger Bypass Valve A 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
35: FaultThe specific fault in that area

What it means

P0035 means the engine control unit has detected a high voltage or a fault in the control circuit for the turbocharger or supercharger bypass valve 'A'. The unit compares the commanded state of the driver circuit with the voltage it actually sees on the circuit, and sets the code when they do not agree, typically because the circuit is shorted to voltage or the driver is faulty. The exact valve layout and how it is controlled depend on the model and engine.

Symptoms

Engine warning light on
Loss of power or reduced boost
Hesitation or surging under acceleration
Whistling, fluttering or blow-off noises from the intake
Engine running in a reduced-power (limp) mode
Poor fuel economy

Possible causes

Faulty bypass (recirculation or blow-off) valve or its solenoid with an internal electrical faultlikely
Wiring fault such as a short to voltage, chafed insulation or damaged harness near the valvelikely
Corroded, loose or damaged connector at the valve or control unitpossible
Blown fuse or a fault in the power supply feeding the valve circuitpossible
Valve mechanically stuck or damaged, causing abnormal circuit readingspossible
Faulty driver circuit inside the engine control unitrare
Outdated control unit software where the manufacturer has issued a known fix for the modelrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine load, speed and temperature when the fault set
Check for other related codes such as boost pressure or wastegate faults, and look up any technical service bulletins for the model
Visually inspect the bypass valve, its vacuum or air connections, and the wiring for heat damage, chafing or oil contamination
Disconnect and inspect the valve connector and control unit connector for corrosion, bent pins and poor tension
Check the relevant fuse and the power supply to the valve against the wiring diagram for the model
Measure the valve solenoid resistance and compare it with the manufacturer specification
Using a wiring diagram, test the control wire for a short to voltage and for continuity back to the control unit
Command the valve with a bidirectional test if supported and check that it moves and the circuit voltage changes as expected

How to fix

Replace the bypass valve or solenoid if it fails electrical or operational tests
Repair or replace damaged wiring and secure the harness away from heat and rubbing
Clean or replace corroded or damaged connectors and terminals
Replace the blown fuse after finding and correcting the cause of the overload
Repair or replace the engine control unit only after wiring and valve faults have been ruled out
Update the control unit software if an applicable manufacturer update addresses the fault

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but expect reduced power and possible stress on the turbocharger from incorrect boost control. Have it diagnosed soon and avoid heavy acceleration until it is repaired.

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