If your OBD-II scanner displays P0035, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected that the turbocharger bypass valve control circuit voltage is higher than expected.
The generic SAE definition for P0035 is:
Turbocharger Bypass Valve Control Circuit High
Depending on the manufacturer, the affected component may also be called the:
- Turbocharger bypass valve
- Compressor bypass valve
- Turbo recirculation valve
- Diverter valve
- Boost bypass valve
- Turbo dump valve
- Electronic blow-off valve
- Compressor recirculation valve
- Turbo bypass solenoid
- Turbo pressure relief valve
Unlike P0033, which indicates a general control circuit malfunction, and P0034, which indicates a low-voltage condition, P0035 specifically means the ECM has detected excessive voltage or insufficient current flow in the bypass valve control circuit.
Common causes include:
- Open bypass valve solenoid
- Open wiring
- Broken control wire
- Disconnected connector
- Corroded electrical terminals
- High circuit resistance
- Failed bypass valve actuator
- Failed relay
- Incorrect replacement bypass valve
- ECM driver failure
Although the vehicle will usually continue driving normally, turbocharger performance, throttle response, and boost control may be affected. Compressor surge may also occur if the bypass valve cannot operate correctly.
Looking for additional OBD-II diagnostic information? Browse our growing library:
- Complete OBD-II Code Library: https://my.prostreetonline.com/dtc-obdii/
- Powertrain (P) Codes: https://my.prostreetonline.com/dtc-obdii/
- Body (B) Codes: https://my.prostreetonline.com/dtc-doctor/b-code-obd-ii-codes/
- Chassis (C) Codes: https://my.prostreetonline.com/dtc-doctor/c-code-obd-ii-codes/
P0035 Quick Facts
| Item | Information |
|---|---|
| OBD-II Code | P0035 |
| Description | Turbocharger Bypass Valve Control Circuit High |
| Category | Powertrain |
| System | Turbocharger Boost Control |
| Severity | Moderate |
| Safe to Drive? | Usually yes |
| Typical Repairs | Wiring repair, bypass valve replacement |
| Estimated Cost | $75–$1,200+ |
What Does P0035 Mean?
P0035 means the ECM has detected that the turbocharger bypass valve control circuit voltage is higher than its calibrated operating range.
On most vehicles, a Circuit High fault indicates the ECM is not seeing the expected current draw from the bypass valve circuit.
Common reasons include:
- Open solenoid winding
- Broken control wire
- Poor connector contact
- High resistance
- Failed relay
- Open power supply
- Failed ECM output driver
Unlike boost pressure codes such as P0299 (Turbo Underboost) or P0234 (Engine Overboost), P0035 monitors the electrical circuit, not actual boost pressure.
What Does the Turbocharger Bypass Valve Do?
The turbocharger bypass valve protects the turbocharger whenever boost pressure is suddenly no longer needed.
When the driver quickly releases the accelerator:
- The throttle plate closes.
- Pressurized intake air has nowhere to go.
- The ECM commands the bypass valve open.
- Pressurized air is redirected back into the intake.
- Compressor surge is prevented.
Without a functioning bypass valve, compressed air can reverse through the compressor wheel, producing compressor surge and placing additional stress on the turbocharger.
Turbocharger Bypass Valve vs Blow-Off Valve
Although often confused, they are slightly different.
Factory Bypass Valve
- Recirculates air
- Quiet operation
- Maintains MAF airflow calculations
- Better emissions compliance
- OEM design
Blow-Off Valve
- Vents air to atmosphere
- Produces the characteristic “whoosh”
- Common on modified turbo vehicles
- May create drivability issues on MAF-equipped engines if improperly installed
Many manufacturers use the terms diverter valve, compressor bypass valve, and turbo bypass valve interchangeably.
How the Turbocharger Bypass System Works
Under acceleration:
- Throttle opens
- Turbocharger creates boost
- Bypass valve stays closed
During throttle lift:
- Throttle closes
- Boost pressure rapidly increases
- ECM commands bypass valve
- Valve opens
- Boost is recirculated
- Turbo speed is maintained
Depending on the manufacturer, the valve may be:
- Vacuum operated
- Electronically controlled
- Solenoid controlled
- Integrated into the turbocharger
How the ECM Detects P0035
The ECM continuously monitors:
- Circuit voltage
- Circuit current
- Solenoid resistance
- PWM duty cycle
- Driver feedback
- Valve response
The ECM may store P0035 when:
- Circuit voltage remains too high
- Current draw is too low
- Solenoid is open
- Control wire is broken
- Connector is disconnected
- Excessive circuit resistance exists
- Driver feedback is incorrect
P0033 vs P0034 vs P0035
These three codes diagnose the same system but identify different electrical faults.
| Code | Description |
| P0033 | Turbocharger Bypass Valve Control Circuit |
| P0034 | Turbocharger Bypass Valve Control Circuit Low |
| P0035 | Turbocharger Bypass Valve Control Circuit High |
Generally:
- P0033 = General circuit malfunction
- P0034 = Low voltage or excessive current
- P0035 = High voltage or insufficient current
Symptoms of P0035
Common symptoms include:
- Check Engine Light
- Reduced turbo response
- Turbo lag
- Hesitation during acceleration
- Reduced boost pressure
- Compressor surge
- Flutter during throttle lift
- Poor throttle response
- Reduced fuel economy
- Limp mode (manufacturer dependent)
- Boost inconsistencies
- Whistling or flutter noises
Some vehicles may display only the Check Engine Light.
Common Causes of P0035
1. Open Bypass Valve Solenoid
The most common cause of P0035 is an internally open solenoid.
Possible causes include:
- Burned winding
- Internal corrosion
- Heat damage
- Manufacturing defect
- Age
2. Broken Control Wire
The control wire may break because of:
- Vibration
- Engine movement
- Rodent damage
- Previous repairs
- Chafing
3. Open Power Wire
Loss of power prevents the valve from operating.
Possible causes include:
- Broken wiring
- Blown fuse
- Failed relay
- Damaged fuse box
4. Loose or Disconnected Connector
Inspect for:
- Connector not fully seated
- Broken locking tabs
- Loose terminals
- Connector separation
5. Corroded Connector
Corrosion creates excessive resistance.
Inspect for:
- Green corrosion
- White corrosion
- Moisture
- Oil contamination
6. High Circuit Resistance
Resistance may result from:
- Corrosion
- Loose terminals
- Damaged wire strands
- Poor splice repairs
Voltage-drop testing is more effective than simple continuity testing.
7. Failed Turbo Bypass Valve
Mechanical failure may include:
- Torn diaphragm
- Broken actuator
- Internal sticking
- Mechanical binding
Some electronically controlled valves contain integrated electronics.
8. Failed Vacuum Solenoid
Vacuum-operated systems use an electrically controlled vacuum solenoid.
Failure may trigger P0035.
9. Vacuum Hose Problems
Inspect for:
- Cracks
- Loose fittings
- Oil contamination
- Collapsed hoses
Although vacuum leaks usually create performance issues rather than electrical faults, they may accompany P0035.
10. Incorrect Replacement Valve
Incorrect aftermarket valves may have:
- Wrong resistance
- Wrong connector
- Incorrect electronics
- Different operating characteristics
Always verify part numbers.
11. Aftermarket Blow-Off Valve Modifications
Some aftermarket kits:
- Eliminate factory electronics
- Modify factory wiring
- Install incorrect resistors
- Remove OEM bypass components
These modifications frequently trigger P0035.
12. Damaged Wiring Harness
Inspect the complete harness for:
- Burned insulation
- Chafed wiring
- Pinched wires
- Previous repairs
- Heat damage
13. Failed Relay
Some manufacturers use a dedicated relay.
Internal relay failure may interrupt power.
14. ECM Driver Failure
Although uncommon, the ECM output transistor may fail.
Always verify:
- Wiring
- Solenoid
- Power
- Ground
before replacing the ECM.
Is P0035 Serious?
P0035 is generally considered moderately serious.
The vehicle normally remains driveable.
However, prolonged driving may lead to:
- Reduced turbo efficiency
- Poor throttle response
- Compressor surge
- Turbocharger wear
- Lower fuel economy
Can You Drive With P0035?
Usually yes.
Avoid aggressive driving if:
- Boost becomes erratic
- Compressor surge occurs
- Turbo flutter increases
- Limp mode activates
Repair should be scheduled as soon as practical.
How to Diagnose P0035
Step 1
Scan for additional trouble codes.
Related turbocharger codes include:
- P0033 – Turbocharger Bypass Valve Control Circuit
- P0034 – Turbocharger Bypass Valve Control Circuit Low
- P0234 – Engine Overboost Condition
- P0299 – Turbocharger Underboost Condition
- P2261 – Turbocharger Bypass Valve Mechanical Performance
- P2262 – Turbocharger Boost Pressure Not Detected
- P2563 – Turbocharger Boost Control Position Sensor
Step 2
Inspect the bypass valve connector.
Check for:
- Bent pins
- Corrosion
- Loose terminals
- Water intrusion
Step 3
Inspect the wiring harness.
Look for:
- Broken wires
- Chafing
- Heat damage
- Pinched sections
Pay particular attention to areas near:
- Turbocharger
- Downpipe
- Exhaust manifold
Step 4
Measure bypass valve resistance.
Compare resistance with manufacturer specifications.
An open circuit indicates a failed solenoid.
Step 5
Verify power supply.
Measure battery voltage at the bypass valve connector.
Step 6
Test the control wire.
Check for:
- Open circuit
- Excessive resistance
- Poor continuity
Step 7
Perform voltage-drop testing.
Inspect:
- Connectors
- Grounds
- Power wires
- Splices
Step 8
Command the bypass valve.
Using a bidirectional scan tool:
- Command valve ON
- Command valve OFF
- Monitor response
Step 9
Inspect vacuum-operated components.
Check:
- Vacuum hoses
- Check valves
- Vacuum reservoir
- Vacuum control solenoid
Step 10
Inspect the turbocharger.
Look for:
- Shaft play
- Oil leakage
- Compressor wheel damage
- Signs of compressor surge
Step 11
Check Technical Service Bulletins
Some manufacturers have released updated bypass valves, revised harnesses or software updates for recurring P0035 issues.
Step 12
Verify Repair
After repairs:
- Clear diagnostic trouble codes.
- Start the engine from cold.
- Road test under boost.
- Monitor desired versus actual boost.
- Confirm bypass valve operation.
- Verify P0035 does not return.
Common Repairs
| Repair | Estimated Cost |
| Wiring repair | $100–400 |
| Connector replacement | $75–250 |
| Vacuum hose replacement | $20–150 |
| Vacuum solenoid replacement | $120–350 |
| Turbo bypass valve replacement | $180–500 |
| Turbo actuator replacement | $300–900 |
| Turbocharger replacement | $1,000–2,500 |
| ECM replacement/programming | $1,000–2,500 |
Common Diagnostic Mistakes
- Replacing the turbocharger before testing the bypass valve
- Ignoring open wiring
- Overlooking connector corrosion
- Installing incorrect aftermarket blow-off valves
- Replacing the ECM before testing the circuit
- Skipping voltage-drop testing
- Failing to verify valve resistance
- Ignoring related boost codes
Vehicles Commonly Affected
P0035 is commonly found on turbocharged vehicles including:
- Audi
- BMW
- Buick
- Cadillac
- Chevrolet
- Ford EcoBoost
- Genesis
- GMC
- Hyundai
- Kia
- Mazda
- Mercedes-Benz
- MINI
- Nissan
- Porsche
- Subaru
- Toyota
- Volkswagen
- Volvo
How to Prevent P0035
To reduce the likelihood of P0035:
- Inspect turbocharger wiring during maintenance.
- Keep wiring secured away from exhaust heat.
- Replace damaged harness clips.
- Repair oil leaks promptly.
- Use OEM-quality bypass valves.
- Avoid poorly designed aftermarket blow-off valve kits.
- Reinstall all heat shields after repairs.
- Inspect electrical connectors for corrosion.
- Repair vacuum leaks promptly.
- Use the correct replacement components.
Frequently Asked Questions
What does P0035 mean?
P0035 indicates the ECM has detected a high-voltage condition in the turbocharger bypass valve control circuit.
What causes P0035?
The most common causes include:
- Open bypass valve solenoid
- Broken wiring
- Open control circuit
- Corroded connector
- Failed relay
Can a bad bypass valve cause P0035?
Yes. An internally open bypass valve solenoid is one of the most common causes.
Can wiring cause P0035?
Yes. Broken or open wiring frequently causes this code.
Can an aftermarket blow-off valve cause P0035?
Yes. Many aftermarket modifications eliminate or alter the factory electronic bypass valve and can trigger this code.
Can vacuum leaks cause P0035?
Vacuum leaks may contribute to bypass valve performance problems, although P0035 is primarily an electrical circuit fault.
Is P0035 serious?
It is generally considered moderately serious. While the vehicle is usually driveable, prolonged compressor surge or poor boost control can shorten turbocharger life.
Can I drive with P0035?
Usually yes, provided there are no severe boost issues or limp mode conditions.
Will clearing P0035 fix it?
No. The code will return if the underlying electrical fault remains.
Can P0035 damage the turbocharger?
If compressor surge occurs repeatedly because the bypass valve cannot operate, turbocharger damage may eventually result.
Final Thoughts
The P0035 code indicates the ECM has detected a high-voltage condition in the turbocharger bypass valve control circuit. In most cases, the problem is caused by an open solenoid, broken wiring, poor electrical connections, or excessive circuit resistance rather than a failed turbocharger.
Begin diagnosis by inspecting the connector and wiring around the turbocharger, as heat damage is common. Verify power and ground, measure bypass valve resistance, perform voltage-drop testing, and command the valve with a bidirectional scan tool before replacing expensive components.
Properly repairing P0035 restores turbocharger response, prevents compressor surge, improves drivability, and helps extend turbocharger life.
Related Articles
Continue troubleshooting turbocharger and boost-control problems with these guides:
- P0033 Code Explained: Turbocharger Bypass Valve Control Circuit
- P0034 Code Explained: Turbocharger Bypass Valve Control Circuit Low
- P0009 Code Explained:
