P0140
PowertrainOxygen Sensormoderate severityO2 Sensor Circuit No Activity Bank 1 Sensor 2
What P0140 Means
The downstream O2 sensor on Bank 1 shows no switching activity.
Symptoms
- Check Engine Light
- No catalyst monitoring
Common Causes
- Faulty sensor
- Heater circuit failure
- Wiring open
Diagnostic Steps
- Test sensor voltage
- Check heater
- Inspect wiring
Where to start: Replace downstream O2 sensor.
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