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What does Error Code P0158 mean?

Moderate Issue
DTC Code P0158 indicates a high voltage issue in the O2 Sensor Circuit for Bank 2 Sensor 2. This occurs when the Engine Control Module (ECM) detects the Heated Oxygen Sensor (HO2S) voltage exceeding 1,050 mV, suggesting a rich fuel mixture.

What are the symptoms of Error Code P0158?

  • Engine Light ON: The check engine light or service engine soon warning light illuminates, indicating an issue with the O2 sensor circuit on Bank 2 Sensor 2.
  • Higher Fuel Consumption: The vehicle may experience increased fuel consumption due to incorrect oxygen sensor readings, which can affect the air-fuel mixture.

What causes Error Code P0158?

  • The rear heated oxygen sensor on Bank 2 may be faulty, leading to incorrect voltage readings.
  • An open or shorted harness in the rear heated oxygen sensor on Bank 2 can disrupt the circuit.
  • Poor electrical connections in the rear heated oxygen sensor circuit on Bank 2 can cause high voltage issues.
  • Variations in fuel system pressure, either low or high, can affect sensor readings.
  • Contaminated fuel can lead to improper combustion and affect sensor performance.
  • Faulty fuel injectors may cause incorrect fuel delivery, impacting sensor voltage.
  • Exhaust gas leaks can alter the oxygen levels detected by the sensor.
  • Engine vacuum leaks can lead to incorrect air-fuel mixture, affecting sensor output.
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How to fix Error Code P0158?

  • Verify DTC Code: Confirm the presence of DTC P0158 using an OBD-II scanner. Ensure no other related codes are present.
  • Inspect Wiring and Connectors: Check the wiring and connectors for the O2 sensor on Bank 2 Sensor 2 for any signs of damage, corrosion, or disconnection.
  • Measure Sensor Voltage: Use a multimeter to measure the voltage at the O2 sensor connector. A high voltage reading indicates a potential short to voltage.
  • Check for Exhaust Leaks: Inspect the exhaust system for leaks near the O2 sensor, as this can affect sensor readings.
  • Test Sensor Operation: Use a scan tool to monitor the O2 sensor's voltage output while the engine is running. Ensure it fluctuates within the expected range.
  • Replace O2 Sensor: If all tests confirm the sensor is faulty, replace the Rear Heated Oxygen Sensor Bank 2 Sensor 2.
  • Clear DTC and Test Drive: Clear the DTC code and perform a test drive to ensure the issue is resolved and the code does not return.
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