I have a check engine light with VSC off ..Took it to mechanic and the code is P0125. He did replace the THERMOSTAT hoping it was a stuck thermostat .After about 100 miles. The same check engine light came on with same code.
SOME THING STRANGE I NOTICED
on cold days when i start up my GX the engine behaves stange as if it is stuggling to breath for a few seconds and then it behaves normal.
IS it the ECT sensor causing it??
No radiator leaks / No low coolant .

|Code P0125 Lexus Possible Causes

• Low engine coolant level
• Leaking or stuck open thermostat
• Faulty Engine Coolant Temperature (ECT) sensor
• Engine Coolant Temperature sensor harness is open or shorted
• Engine Coolant Temperature sensor electrical circuit poor connection