P0039 Fault Code

P0039 OBD-II Trouble Code Short Description

Turbo/Super Charger Bypass Valve Control Circuit Range/Performance

What does trouble code P0039 mean?

The P0039 fault code refers to a problem with the turbocharger or supercharger bypass valve control circuit. This code typically appears on turbocharged or supercharged vehicles.

The bypass valve control circuit is responsible for regulating the pressure of the compressed air from the turbocharger or supercharger. It ensures that the right amount of air is delivered to the engine for optimal performance and fuel efficiency. The valve opens and closes as needed to divert excess air away from the engine.

When the control circuit encounters a range or performance issue, it means that there is a problem with the valve or the electrical components controlling it. This could be due to a faulty valve, a wiring issue, or a problem with the control module.

To diagnose and resolve the P0039 code, you should:

  1. Perform a visual inspection of the turbocharger or supercharger bypass valve and its wiring for any signs of damage or loose connections.
  2. Test the bypass valve and its control solenoid using a multimeter to check for proper resistance and functionality.
  3. Inspect the wiring harness and connectors for any damage or corroded pins.
  4. Check the control module for any fault codes or issues by using a professional diagnostic tool.

Once the problem has been identified, the necessary repairs or replacements can be made. This may involve repairing or replacing the bypass valve, repairing damaged wiring, or replacing the control module. It is recommended to consult a qualified mechanic or dealership for an accurate diagnosis and proper repair of the P0039 fault code.


What are the symptoms of the P0039 code?

The P0039 fault code indicates a problem with the turbo/supercharger bypass valve control circuit. Here are some common symptoms associated with this fault code:

  • Check Engine Light (CEL) is illuminated
  • Lack of power or reduced engine performance
  • Turbocharger or supercharger not engaging or operating properly
  • Increased fuel consumption
  • Rough or unstable idle
  • Engine may stall or hesitate during acceleration

Please note that these symptoms may vary depending on the make and model of the vehicle. It is always recommended to consult a professional mechanic to diagnose and repair the issue accurately.


What causes the P0039 code?

The P0039 fault code in cars is typically caused by one or more of the following issues:

  1. Faulty turbocharger or supercharger bypass valve: The bypass valve controls the flow of compressed air around the turbocharger or supercharger, depending on the engine's needs. If the valve is stuck open or closed, it can lead to improper engine performance and trigger the P0039 code.

  2. Wiring or connector issues: A damaged or loose connection between the bypass valve and the engine control module (ECM) can cause circuit range or performance problems, triggering the P0039 code.

  3. ECM software issue: Sometimes, the fault may be due to a software glitch in the ECM. The ECM controls the operation of various engine components, including the bypass valve. If there is a programming error, it can result in the P0039 code being set.

  4. Vacuum leak: A vacuum leak in the intake or bypass system can affect the turbocharger or supercharger's performance, leading to the P0039 code.

  5. Mechanical issues: Any mechanical problems with the turbocharger or supercharger itself, such as a damaged impeller or worn-out bearings, can affect the operation of the bypass valve and trigger the P0039 fault code.

It is important to note that the specific cause of the P0039 code may vary depending on the make and model of the vehicle. A professional diagnostic scan tool and expertise are usually required to accurately diagnose and repair the issue.

Possible Solutions

How to fix P0039?

To fix the P0039 fault code, which indicates a Turbo/Supercharger Bypass Valve Control Circuit Range/Performance issue, follow these steps:

  1. Inspect the bypass valve: Check for any signs of damage or wear on the bypass valve itself. Ensure that it is functioning properly and moves freely. Clean or replace the valve if necessary.

  2. Inspect the vacuum lines: Check all the vacuum lines connected to the bypass valve for any leaks, cracks, or loose connections. Secure or replace any damaged lines.

  3. Check the wiring harness: Inspect the wiring harness connected to the bypass valve for any frayed wires, loose connections, or corrosion. Repair or replace any damaged wiring.

  4. Test the bypass valve control solenoid: Use a multimeter to check the resistance of the bypass valve control solenoid. Compare the readings with the manufacturer's specifications. If the readings are outside the acceptable range, replace the solenoid.

  5. Scan for additional fault codes: Use a diagnostic scanner to check for any additional fault codes related to the turbocharger system. Address any additional issues that may be contributing to the fault code.

  6. Clear the fault code: Once you have addressed any potential causes and made necessary repairs, use a diagnostic scanner to clear the fault code. This will reset the vehicle's onboard computer and allow you to monitor for any recurring issues.

Note: If you're not confident in your ability to perform these tasks, it's recommended to consult a qualified mechanic or technician for assistance. They will have the necessary tools and expertise to diagnose and fix the issue correctly.