P0138
O2 Sensor Circuit High Voltage Bank 1 Sensor 3
Generic code
Fuel and Air Metering
Medium severity
Moderate repair
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What P0138 means
- The fault code P0138 indicates that there is an issue with the oxygen sensor circuit for bank 1, sensor 2, resulting in a high voltage signal. This may cause the engine to run poorly, reduce fuel efficiency, and increase emissions.
Possible symptoms
- Illuminated check engine light
- Poor engine performance
- Reduced fuel efficiency
- Increased emissions
- Rough idling or stalling
Possible causes
- Failed oxygen (O2) sensor
- Malfunctioning sensor wiring or connections
- Engine vacuum leaks
- Faulty catalytic converter
- Engine misfire or running rich
Related parts
- Oxygen Sensor: This is one of the parts that fails very commonly. It measures the amount of oxygen to ensure proper combustion. Problems in the Oxygen Sensor lead to poor fuel economy
Possible solutions
- Replace the oxygen sensor
- Check and repair any damaged wiring or connections
- Repair any engine vacuum leaks
- Replace the catalytic converter if necessary
- Address any engine misfire or running rich issues
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P0138 on OBD DashX
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