Definition of error code P0158
High voltage oxygen sensor circuit (Bank 2 sensor 2)
What does fault code P0158 mean?
- The P0158 fault code occurs when the sensor is under high voltage for too long.
- This oxygen sensor is located downstream of the catalytic converter. It sends information to the power control module (PCM) about the efficiency and level of oxygen released by the catalytic converter.
- When the engine is idling, it means that there is more oxygen than fuel in the exhaust gases. When the engine is running well, this means that there is more fuel than oxygen in the exhaust gases.
- If the sensor is working properly, it switches from low voltage (high oxygen level) to high voltage (low oxygen level).
What causes code P0158?
- Rear oxygen sensor malfunction
- Malfunction in the heating circuit of the rear oxygen sensor.
- Engine coolant temperature sensor malfunctioning
- Short circuits, breaks or exposed oxygen sensor wires
- Excessive fuel pressure
- Power control module (PCM) upgrade required
- Power control module (PCM) failure.
What are the symptoms of the P0158 code?
- The check engine light is on
- Fuel economy reduction
- Engine runs poorly
- Engine coolers
- Engine Interlocks
How can a mechanic diagnose the P0158 code?
- The mechanic will use an OBD-II scanner to extract all the current fault codes that have been stored by the power control module (PCM).
- They will check the live data from the oxygen sensor on the scanner. They will check the voltage reading to see if the oxygen sensor changes from low voltage to high voltage every few seconds.
- When the engine coolant temperature sensor fault code is also present, they will check the live data on the scanner to see if the engine temperature is adequate.
- The rear oxygen sensor wiring harness is checked for short circuits, breaks, or exposure.
- The fuel pressure is checked for higher than normal fuel pressure.
- Run the manufacturer’s diagnostic procedures on the power control module (PCM) to determine if it needs to be replaced or upgraded.
Most common errors when diagnosing the P0158 code
- Replacement of the oxygen sensor before considering other necessary repairs.
- Failure to wait properly for short, broken, or exposed wires.
How serious is the P0158 code?
The P0158 fault code is considered serious if it causes the car to stall. This problem should be fixed as soon as possible to avoid driving problems.
What repairs can fix a P0158 code?
- Replace the rear oxygen sensor
- Repair shorted, damaged, or exposed oxygen sensor cables.
- Make necessary repairs to remove excessive fuel pressure.
- Replace the engine coolant temperature sensor, if necessary.
- Replace or upgrade the power control module (PCM), if necessary.
Additional notes on code P0158
The oxygen sensor kit and propane tank will be needed to remove the oxygen sensor if it has stalled in the exhaust or is difficult to access.
