p0128
Moderate
Peugeot · SUVs
Coolant Thermostat (Coolant Temp Regulation) Malfunction
Quick Answer
Error code P0128 on your Peugeot SUVs means: Coolant Thermostat (Coolant Temp Regulation) Malfunction. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Monitor coolant temperature on scanner
2
Feel radiator hoses for proper temperature
3
Check coolant level and condition
4
Test thermostat operation in hot water
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 temperature sensor
Engine coolant
Gasket sealant
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