P0138
O2 Sensor Circuit High Voltage Bank 1 Sensor 2
1999-2000 BMW 323i E46 2.5L I6 🇨🇦
Moderate SeverityPowertrain
Description
The downstream O2 sensor on Bank 1 is reading high voltage consistently.
Symptoms
- Check Engine Light
- Failed emissions
- May indicate catalyst failure
Common Causes
- Faulty sensor
- Catalytic converter failure
- Rich running condition
Diagnostic Steps
- Test sensor voltage
- Check catalyst efficiency
- Monitor upstream vs downstream O2 patterns
Repair Notes
Replace sensor. If catalyst failed, replace catalytic converter.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P0138 on Other Vehicles
Common Questions
What does code P0138 mean on a 1999-2000 BMW 323i E46?
P0138 stands for "O2 Sensor Circuit High Voltage Bank 1 Sensor 2". The downstream O2 sensor on Bank 1 is reading high voltage consistently.
What are the symptoms of P0138 on a BMW 323i E46?
Common symptoms of P0138 include: Check Engine Light, Failed emissions, May indicate catalyst failure.
What causes P0138 on a 1999-2000 BMW 323i E46?
Common causes of P0138 include: Faulty sensor, Catalytic converter failure, Rich running condition.