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

Check Engine Light

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?

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