The P0033 code refers to an issue within the Turbocharger Bypass Valve Control Circuit, indicating that the control circuit is out of its expected range or performance. This can lead to symptoms such as loss of power, hesitation during acceleration, rough idle, and even intermittent stalling in turbocharged vehicles.
P0033 quick overview
| Meaning | P0033 – Turbocharger Bypass Valve Control Circuit |
| Is it serious? | Yes, this code can significantly impact the vehicle’s performance by affecting turbocharger efficiency and engine power output. |
| Possible causes | – Faulty turbocharger bypass valve – Wiring or connector issues in the bypass valve control circuit – Boost leaks in the intake or charge piping – Underboost conditions due to other turbocharger system faults |
| How to diagnose? | Inspect the turbocharger bypass valve wiring and connectors for any signs of damage or poor connections. Test the turbocharger bypass valve to ensure it operates within the manufacturer’s specifications for resistance and function. Check for boost leaks in the intake system and charge piping using a smoke test. Assess other related systems, such as fuel delivery or engine compression, to rule out additional causes of underboost conditions. |
P0033 Meaning
The P0033 code means there’s a problem with the turbocharger’s bypass valve circuit. This valve helps manage the turbo’s pressure by redirecting excess air when it’s not needed. Issues with this valve or its wiring can cause power loss or erratic performance. To fix it, mechanics check the valve, its connections, and the turbo system.
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How to fix P0033 – learn from mechanics
I looked into P0033 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Audi P0033
Vehicle information 2015 Audi A4 Quattro 2.0L Turbocharged
Issue + repair history
- Experiencing loss of power and hesitation during acceleration
- Previous repairs include replacing turbocharger boost sensor and cleaning intake manifold
- Current symptoms: CEL on, code P0033
Other OBD2 Codes + Test Results
- P0033: Turbocharger Bypass Valve Control Circuit
- P0299: Turbocharger/Supercharger Underboost Condition
- Live data shows erratic turbocharger bypass valve control signal
Mechanic suggestions
- Inspect the turbocharger bypass valve wiring and connectors
- Test the turbocharger bypass valve for proper operation and resistance
- Check for boost leaks in the intake and charge piping
- Perform a smoke test to detect vacuum leaks
Final fix
- Replaced faulty turbocharger bypass valve, addressed boost underboost condition by fixing boost leaks, cleared codes, problem resolved.
Case #2: Ford P0033
Vehicle information 2017 Ford F-150 3.5L EcoBoost
Issue + repair history
- Experiencing rough idle and lack of power
- Previous repairs include replacing ignition coils and spark plugs
- Current symptoms: CEL on, code P0033
Other OBD2 Codes + Test Results
- P0033: Turbocharger Bypass Valve Control Circuit
- P0299: Turbocharger/Supercharger Underboost Condition
- Live data shows erratic turbocharger bypass valve control signal
Mechanic suggestions
- Inspect the turbocharger bypass valve wiring and connectors
- Test the turbocharger bypass valve for proper operation and resistance
- Check for boost leaks in the intake and charge piping
- Perform a compression test to check engine health
Final fix
- Replaced faulty turbocharger bypass valve, addressed boost underboost condition by fixing boost leaks, cleared codes, problem resolved.
Case #3: Subaru P0033
Vehicle information 2016 Subaru WRX STI 2.5L Turbocharged
Issue + repair history
- Experiencing loss of power and intermittent stalling
- Previous repairs include replacing turbocharger boost solenoid and cleaning throttle body
- Current symptoms: CEL on, code P0033
Other OBD2 Codes + Test Results
- P0033: Turbocharger Bypass Valve Control Circuit
- P0299: Turbocharger/Supercharger Underboost Condition
- Live data shows erratic turbocharger bypass valve control signal
Mechanic suggestions
- Inspect the turbocharger bypass valve wiring and connectors
- Test the turbocharger bypass valve for proper operation and resistance
- Check for boost leaks in the intake and charge piping
- Perform a fuel pressure test to ensure proper fuel delivery
Final fix
- Replaced faulty turbocharger bypass valve, addressed boost underboost condition by fixing boost leaks, cleared codes, problem resolved.
How to diagnose P0033
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Explanation |
|---|---|
| Inspect wiring and connectors | Look for damaged wiring or poor connections that could affect signal transmission. |
| Test bypass valve operation | Verify the valve’s functionality and resistance specifications. |
| Check for boost leaks | Identify any leaks in the intake system that could lead to underboost conditions. |
| Assess related systems | Rule out additional factors that could contribute to the problem, such as fuel delivery issues or engine compression. |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko