BMW DTC P0138 – O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
DTC P0138 meaning on BMW
The Diagnostic Trouble Code (DTC) P0138 in a BMW indicates that the O2 sensor circuit for Bank 1 Sensor 2 is registering a high voltage condition. This sensor is located downstream of the catalytic converter and is responsible for monitoring the oxygen levels in the exhaust gases.
BMW DTC P0138 symptoms
Symptoms of a DTC P0138 on a BMW may include:
- Illuminated Check Engine Light
- Decreased fuel efficiency
- Engine running rough or misfiring
- Failed emissions test
BMW DTC P0138 causes
Common causes of a DTC P0138 on a BMW include:
- Faulty O2 sensor
- Wiring or connector issues in the O2 sensor circuit
- Exhaust leaks near the sensor
- Engine running rich
BMW DTC P0138 seriousness
While a DTC P0138 may not cause immediate drivability issues, it can lead to decreased fuel efficiency and increased emissions. Ignoring this code can potentially cause damage to the catalytic converter over time.
How to diagnose DTC P0138 on BMW
To diagnose a DTC P0138 on a BMW, you can:
- Use a scan tool to read the code and check freeze frame data
- Inspect the O2 sensor wiring and connectors for damage
- Perform a visual inspection for exhaust leaks near the sensor
- Test the O2 sensor using a multimeter
How to fix DTC P0138 on BMW
To fix a DTC P0138 on a BMW, you may need to:
- Replace the faulty O2 sensor
- Repair any damaged wiring or connectors in the O2 sensor circuit
- Fix any exhaust leaks near the sensor
- Address any underlying engine issues causing a rich condition
How to erase DTC P0138 on BMW
To erase a DTC P0138 on a BMW, you can:
- Use a scan tool to clear the code after the underlying issue has been fixed
- Disconnect the battery for a few minutes to reset the ECU and clear the code