Powertrain
generic / SAE
P0126
Insufficient Coolant Temperature for Stable Operation
Coolant temperature stays below the value expected for stable engine operation. Almost always points to a thermostat stuck open or a sensor reading lower than the actual engine temperature.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 26
Possible causes
- Thermostat stuck open high
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 80–400 €
- Estimated time: 0.5–2.5 h
- Component: thermostat
- Component: coolant temperature sensor
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012