P0597moderate severityPowertrain
Thermostat Heater Control Circuit/Open
on 2015 Kia Forte 1.8L I4 · FWD
What this code means
The PCM detected an open in the thermostat heater control circuit. The heated thermostat element cannot be energized to regulate coolant temperature.
Symptoms
- Check engine light on
- Slow engine warm-up
- Coolant temperature fluctuations
Common causes
- Open thermostat heater wiring
- Faulty heated thermostat
- Poor connector contact
- PCM control circuit fault
Diagnostic steps
- Scan for thermostat heater codes
- Check heater circuit continuity
- Inspect thermostat connector
- Test heater element resistance
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