What it means
The turbocharger or supercharger bypass valve control circuit is reporting voltage above the expected range.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The turbocharger bypass valve control circuit commands a valve that diverts air around the compressor to manage boost. The module sets P0035 when circuit voltage is higher than expected; a wire shorted to battery voltage, an open circuit, or a poor connector can prevent reliable valve control.
Common causes
Most likely first.
- Signal wire shorted to battery voltage
- Open circuit in wiring or solenoid
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Reduced engine performance
How to diagnose it
- Save freeze-frame data and look for related boost-control or electrical codes before clearing the fault.
- Inspect the bypass valve connector and harness for a power wire contacting the control circuit, pinched insulation, corrosion, or a disconnected plug.
- Check the relevant fuse and connector terminals, then trace the circuit using the vehicle wiring diagram.
- Test the control circuit for a short to battery voltage and for opens, following the manufacturer's isolation procedure.
- If wiring is intact, test the bypass valve solenoid or actuator and module output to identify the source of the high reading.
Common fixes
- Repair a control wire shorted to battery supply or trapped against a power wire.
- Reconnect the bypass valve plug and secure the harness away from hot or moving parts.
- Replace damaged or corroded connector terminals.
- Replace the bypass solenoid or actuator if its circuit is open or otherwise fails testing.
- Repair a confirmed module output fault after the circuit and actuator have been checked.
Can I keep driving?
If the vehicle runs normally, drive gently and avoid hard acceleration or towing because bypass control and boost may be affected. Stop if power becomes unpredictable or the engine develops serious running symptoms.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.