P0138moderate severityPowertrain
O2 Sensor Circuit High Voltage Bank 1 Sensor 2
on 2016 Hyundai Tucson 2.4L I4 · AWD
What this code means
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.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1