P0161 – O2 Sensor Heater Circuit (Bank 2 Sensor 2)
Description
The ECM detects a malfunction in the heater circuit of the downstream O2 sensor on Bank 2.
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Compare Diagnostic ScannersSymptoms
- Poor fuel economy
- Delayed catalyst monitoring
- Check engine light
Causes
- Failed heater element
- Blown fuse
- Open or shorted wiring
- Connector issues
Diagnosis
- Check heater fuse and power supply
- Measure heater resistance
- Verify power and ground at sensor connector
- Inspect wiring and connector
Repair
- Replace downstream O2 sensor if heater is faulty
- Repair wiring or connector
- Replace fuse after correcting cause
