p0128
Easy Fix
Acura · Sedans
Coolant Thermostat (Coolant Temp Regulating Thermostat) Circuit Malfunction
Quick Answer
Error code P0128 on your Acura Sedans means: Coolant Thermostat (Coolant Temp Regulating Thermostat) Circuit Malfunction. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Monitor coolant temperature at startup
2
Feel radiator hose for temperature change
3
Test coolant temperature sensor resistance
4
Check cooling fan operation
5
Replace thermostat if temperature regulation fails
Pro Tip
This is a common issue that most users can resolve without specialized tools. Try the first step before moving on to more complex solutions.
Parts You May Need
Thermostat
Coolant
Thermostat housing gasket
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