Engine Error
P0126
Insufficient Coolant Temperature for Stable Operation
Severity
Low
Symptoms
Heater blows cold air, temp gauge reads low, decreased fuel economy
Common Causes
- Thermostat stuck open
- Low engine coolant level
- Faulty engine coolant temperature (ECT) sensor
- Cooling fans running continuously
How to Fix
- 1 Replace engine thermostat
- 2 Top off and bleed cooling system
- 3 Replace ECT sensor
- 4 Test fan relay circuit
Estimated Repair Cost
USD
$50
–
$300
Thermostat replacement: $100 - $300; Coolant: $50