p0128
Moderate
Alfa Romeo · Sedans & Sports Cars
Coolant Thermostat (Coolant Temp Regulating Thermostat) Performance
Quick Answer
Error code P0128 on your Alfa Romeo Sedans & Sports Cars means: Coolant Thermostat (Coolant Temp Regulating Thermostat) Performance. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Check coolant level and top off if needed
2
Verify coolant temperature sensor readings
3
Test thermostat opening and closing
4
Check water pump operation
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
Gaskets
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