p0128
Moderate
Volvo · SUVs
Coolant Thermostat (Coolant Temp Regulating Thermostat) Circuit Open
Quick Answer
Error code P0128 on your Volvo SUVs means: Coolant Thermostat (Coolant Temp Regulating Thermostat) Circuit Open. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
Likely Causes
How to Fix It
1
Check coolant level and top up if needed
2
Test thermostat by monitoring coolant temp
3
Feel radiator hose temperature
4
Inspect water pump operation
5
Replace thermostat if stuck open
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
thermostat
coolant
water pump
Related Error Codes