DTC P0035 – Turbocharger Bypass Valve Control Circuit high

🔧 Most commen causes 

1. Bypass/Wastegate Solenoid open circuit

2. Broken wire or unplugged connector

3. Corroded or loose connector pins

4. Short to power

5. Faulty bypass valve (diverter valve)

6. ECM driver issue (less common)

🛠️ Step-by-step diagnosis

1. Check the Bypass Valve Connector

Inspect for:

Loose connection

Corroded pins

Oil contamination

Broken locking tab

Clean and refit securely.

👉 Clear code and test drive

2. Measure Solenoid Resistance

Typical boost/bypass solenoid resistance: 20–40 Ω (varies by manufacturer).

If open / infinite resistance → Replace the solenoid.

3. Check Power Supply

Using a multimeter:

Key ON

One pin should have battery voltage (12V)

If no power:

Check fuse

Check wiring from ECM supply

4. Check Control Wire (Signal)

The ECM control s the ground side (usually PWM).

Test:

Backprobe signal wire

Should show pulsing voltage 2–12V depending on boost demand

If voltage stuck high (>12V):

Open circuit

Broken wire

ECM driver fault

5. Check the Vacuum Lines (if vacuum-type solenoid)

Cracked / loose vacuum hoses

Blocked vacuum supply

Leaking diaphragm in bypass actuator

6. Check the Turbo Bypass/Diverter Valve

Stuck open/closed

Torn diaphragm

Mechanical failure

🚗 Typical symptoms seen

Low boost

Overboost / limp mode

Whistling sound

Poor acceleration

Check Engine Light

🔧 Best quick fixes

Most common successful repairs in workshops:

1. Replace bypass/wastegate solenoid

2. Repair wiring (open circuit)

3. Clean/repair connectors

4. Replace diverter valve (on VW/Audi TSI mostly)

Welcome to madurai car service 💐🙏.