What does code P0138 mean?
Excessively high voltage detected from the rear oxygen sensor.
OBD-II Code
P0138 — Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2
Excessively high voltage detected from the rear oxygen sensor.
Common symptoms
- Strong exhaust odor
- rich mixture
- high fuel consumption
Possible causes
- Signal shorted to voltage
- damaged sensor
- excessive fuel delivery
Initial recommendation
Inspect wiring and verify fuel pressure.
Safety notice
This information is for guidance only and does not replace a physical vehicle inspection or diagnosis by a qualified mechanic. If the vehicle has severe power loss, smoke, a fuel odor, overheating, brake or steering problems, or any unsafe behavior, avoid driving it and seek professional inspection.
Analyze this code with MecaOBD
Use the app to combine code P0138 with your vehicle's actual symptoms for more complete diagnostic guidance.
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