P0042low severityPowertrain
HO2S Heater Control Circuit (Bank 1 Sensor 3)
on 2015 Kia Forte 1.8L I4 · FWD
What this code means
The heater control circuit for the third oxygen sensor on bank 1 has a general fault. Sensor heating is impaired, delaying accurate exhaust readings.
Symptoms
- Check engine light on
- Failed emissions readiness
- Minor fuel economy loss
Common causes
- Faulty O2 sensor heater
- Blown heater fuse
- Wiring or connector damage
- Failed PCM driver
Diagnostic steps
- Scan and confirm code
- Check heater circuit fuse
- Measure heater resistance and voltage
- Inspect wiring to sensor 3
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P0002
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P0003
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P0004
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P0005
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P0006
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P0007
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P0008
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P0010
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