2002 Lexus ES300 Q&A
2002 Lexus ES300 Question: Troubleshooting help with a coolant thermostat problem. P0128 code.
The check engine light used to go off and on periodically. A month ago it came on and has not gone off. the code reads P0128, a coolant thermostat problem present. However, the engine temp gauge on my dash has been working perfectly normal this whole time. I am guessing it is a faulty sensor since, like I said, the check engine light used to go on and off periodically. What troubleshooting things can I do to find the solution? - ant5110
Monitor the readings for coolant temp. sensor (for PCM-NOT fan) WITH scanner(live data) and see if it's opening to soon. Car may not be warming up fast enough for OBDII specs , and setting the code. Has t-stat ever been changed (with Toyota/Lexus part)? - ziptie12