Engine Error
P0128
Coolant Thermostat (Coolant Temp Below Regulating Temperature)
Severity
Low
Symptoms
Engine taking long to warm up, heater blowing cool air, low temp gauge
Common Causes
- Thermostat stuck open
- Faulty coolant temperature sensor
- Incorrect coolant level
- Fan running constantly
How to Fix
- 1 Replace thermostat
- 2 Flush and refill coolant
- 3 Replace coolant temp sensor
- 4 Inspect cooling fan relay
Estimated Repair Cost
USD
$150
–
$400
Thermostat and labor: $150 - $300; Sensor: $100 - $200