p0128
Moderate
Lexus · SUVs
Coolant Thermostat (Coolant Temp Regulating Thermostat) Circuit
Quick Answer
Error code P0128 on your Lexus SUVs means: Coolant Thermostat (Coolant Temp Regulating Thermostat) Circuit. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Monitor coolant temperature with scanner
2
Feel radiator hoses to check temperature
3
Drain and refill coolant system
4
Replace thermostat housing
5
Test new thermostat operation
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
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