P0239 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Malfunction

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Cost of diagnosing the P0239 code

P0239 is a diagnostic trouble code (DTC) for "Turbocharger Boost Sensor B Circuit Malfunction". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

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P0239 code definition

Turbocharger Boost Sensor B Circuit Malfunction

What the P0239 code means

P0239 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects an intake boost pressure sensor B input malfunction when compared to the manifold pressure sensor (MAP) when the engine is at idle; turbocharger boost should be zero.

What causes the P0239 code?

  • The turbo boost sensor B and the MAP sensor voltage input do not correlate the same reading with the engine at idle or when the key is first turned on and the engine is off.

  • The turbo boost pressure sensor B is contaminated or clogged.

  • The turbo boost pressure sensor B is slow to respond to changing pressure, most likely from age deterioration.

What are the symptoms of the P0239 code?

  • The Check Engine Light will be illuminated and the code will be set in memory.

  • The engine turbocharger boost pressure may be turned off by the ECM causing the engine to lack power on acceleration.

How does a mechanic diagnose the P0239 code?

  • Scans codes and documents the freeze frame data in order to verify the problem
  • Clears the codes to verify whether the concern comes back
  • Checks the operation of the boost pressure sensor compared to the MAP sensor
  • Checks the turbo boost sensor B for blockage of the sensor port
  • Checks the turbo boost sensor B connector for loose or corroded pins

Common mistakes when diagnosing the P0239 code?

Follow these simple guidelines to prevent misdiagnosis:

  • Check the boost pressure sensor hose for obstructions or kinks.

  • Verify the electrical connections to the sensor are secure and pressure hoses are not leaking or kinked.

How serious is the P0239 code?

  • The boost pressure in the intake can give you a lot of power. If the turbo boost sensor B is malfunctioning, then the ECM may disable the turbo boost and you would have a lack of power.

What repairs can fix the P0239 code?

  • Replacing the boost sensor if it is not giving the correct input pressure reading to the ECM

  • Repairing or replacing the hoses and connections to the turbo boost sensor if kinks or blockage of the lines are present

  • Repairing the wiring to the sensor or replacing the connection

Additional comments for consideration regarding the P0239 code

Code P0239 is triggered by the intake boost sensor B indicating a malfunction condition that the ECM cannot determine the true cause. The most common failure is the boost sensor in most cases.

Need help with a P0239 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

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