P0146low severityPowertrain
O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 3)
on 2000 Audi A6 2.7L Turbo V6 · AWD
What this code means
The third oxygen sensor on bank 1 shows no activity. The signal is flat and not switching as expected.
Symptoms
- Check engine light on
- Failed emissions test
- No downstream O2 activity
Common causes
- Faulty oxygen sensor
- Open circuit in wiring
- Blown fuse or heater fault
- Corroded connector
Diagnostic steps
- Monitor O2 sensor signal for activity
- Check sensor heater circuit and fuse
- Inspect wiring and connector
- Replace sensor if inactive
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