P0439low severityPowertrain
Catalyst Heater Control Circuit (Bank 2)
on 2023 Chevrolet Bolt EUV 65 kWh Single Motor FWD · FWD
What this code means
There is a fault in the catalyst heater control circuit on bank 2. The heater helps the converter reach operating temperature quickly for emissions.
Symptoms
- Check engine light on
- Failed emissions test
- Higher emissions on cold start
Common causes
- Faulty catalyst heater element
- Wiring or connector damage
- Blown fuse or relay
- Bad PCM
Diagnostic steps
- Retrieve code and freeze frame
- Inspect heater circuit wiring and fuse
- Test heater element resistance
- Repair circuit or replace component
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