P0050low severityPowertrain
HO2S Heater Control Circuit Bank 2 Sensor 1
on 2020 Mazda Mazda3 2.5L I4 · FWD
What this code means
The PCM detected a malfunction in the heater circuit of the upstream O2 sensor on Bank 2.
Symptoms
- Check Engine Light
- Poor fuel economy
- Longer warmup emissions
Common causes
- Faulty O2 sensor heater
- Blown fuse
- Wiring damage
Diagnostic steps
- Check fuse
- Test heater resistance
- Inspect wiring
- Test PCM output
Repair notes
Replace O2 sensor or repair wiring.
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