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P0242 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit High

Check Engine Light

P0242 code definition

Turbocharger Boost Sensor B Circuit High

What the P0242 code means

P0242 is a generic OBD-II code which indicates that the engine control module (ECM) detected the intake boost pressure sensor B input circuit out of specifications; possibly due to an open circuit, or high voltage condition in the circuit from a short to power.

What causes the P0242 code?

  • The turbo boost pressure sensor B has an internal open circuit

  • The turbo boost pressure sensor B connector is damaged causing an open circuit

  • The turbo boost pressure sensor B wiring is shorted to power between the sensor and the ECM

What are the symptoms of the P0242 code?

  • The Check Engine Light will be illuminated and code P0242 is set in the ECM memory

  • The engine turbo boost may be turned off by the ECM and the engine will lack power

  • The engine will lack power during acceleration

How does a mechanic diagnose the P0242 code?

  • Scans codes and documents the freeze frame data in order to verify the problem

  • Clears the DTC codes to verify whether the concern comes back

  • Checks the operation of the boost pressure sensor signal and compares it to the MAP sensor at engine idle to see if the readings are the same

  • Checks the turbo boost sensor wiring and connector for any signs of shorts to power in the harness

  • Checks the turbo boost sensor connector for corroded pins in the connector that may cause shorting of power in the signal circuit

  • Compares readings to specifications on the sensor data scan

Common mistakes when diagnosing the P0242 code

Follow these simple guidelines to prevent misdiagnosis:

  • Try disconnecting the sensor to see if the short to power and code goes away or changes

  • Check the harness for melting from loose or hanging wire looms; on the exhaust in most cases

How serious is the P0242 code?

  • A short to a power source in the sensor circuit can cause the engine ECM to get internally burned out if the circuit short went over 5 volts.

  • If the ECM gets burned out, then the vehicle may stall and not start (worse case).

  • The failed sensor or circuit will cause the turbocharger to not allow boost to the engine.

What repairs can fix the P0242 code?

  • Replacing the boost sensor if it was open internally and not giving the correct input pressure voltage reading to the ECM

  • Repairing the wiring harness if any shorts to power were found, and securing the harness from getting damaged (Check the ECM for voltage spike damage)

  • Replacing any broken connectors causing the short or open circuits

  • Replacing a shorted ECM, if it was shorted internally, and repairing the cause of the short

Additional comments for consideration regarding the P0242 code

Code P0242 is triggered by the intake boost sensor circuit shorted to power or open completely, causing the signal to the ECM to go way above, or below voltage specifications. The most common failure is the boost sensor internally open, or the harness has been shorted to power on the exhaust manifold.

Need help with a P0242 code?

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