Hi i have a 2001 GS300 with 120k and the CEL light is on and its a P0125 Code: Insufficient Coolant Temperature For Closed Loop Fuel Control. I've been researching the web and a lot of people say it might be the O2 sensor and some say its the ECT sensor.

The car drives fine, it idles a little rough. I can feel the steering wheel vibrating a little bit when i stop at a red light. The temperature gauge is normal at the middle. Also I dont know if this is common for all Lexus but when i turn my AC on the fan doesnt stop, it stays on until i turn off my AC. Any help is appreciated, thanks in advance.

 

I had the same problem about a year back. check the connection of the o2 sensor right near the firewall on the passenger side (behind intake tubing). the connector i had there the wires became brittle and had a break in one of the wires. the shop had to resolder a new one to the connector and everything was perfect after. I changed all of my o2's thinking that was it, for me it wasnt but its cheaper to get the voltage test than get 4 new o2's.

 

I have the same problem for a year now.. I changed the ECT and it did nothing... I guess I should really take a look at the o2 sensors.

 

i'll take a look at the o2 sensors, thanks

 

its not the sensor itself for my car, it was the connector which you plug the o2 sensors connector to (female end) that had the break. it was not visibly noticeable & hard to tell until i brought the car to the shop and they did a whole voltage test on each of my wiring and notice one was dead.