p0128
Moderate
Buick · SUVs
Coolant Thermostat (Coolant Temp Regulation)
Quick Answer
Error code P0128 on your Buick SUVs means: Coolant Thermostat (Coolant Temp Regulation). 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
2
Inspect coolant hoses for leaks
3
Test thermostat operation with heat test
4
Replace thermostat if stuck
5
Verify coolant temperature sensor
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
Coolant
Thermostat
Coolant temperature sensor
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