DTC P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) [04/2013 - 06/2014]: Description
WARNING: This page is about a different car, the 2015 Lexus IS 250 and 2014 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.
HINT:
This DTC relates to the water inlet with thermostat sub-assembly.
This DTC is stored when the engine coolant temperature does not reach 75°C (167°F) despite sufficient engine warm-up time having elapsed.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory |
|---|---|---|---|---|---|
| P0128 | Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) | All of the following conditions are met for 5 seconds (2 trip detection logic): (a) Cold start (b) The engine is warmed up (c) The engine coolant temperature is less than 75°C (167°F) |
|
Comes on | DTC stored |