p0125, p0173, p0115
 

Hi guys....
My 01 montero limited 3.5 is throwing the 125, 115, and 173. Happens on highway drives and goes off when back on regular road city driving. I have replace the thermostat and engine coolent temp sensor.
I replaced both parts while light was not on. I did not clear the codes with my OBDII scan tool. But light wasnt on. I drove on the highway again and same code came back. Im just not sure where to go. Any help would be greatful. Thank you in advanced!!!

Sounds like you have a problem with the temperature circuitry. Your sensor could be just fine, but if there is an issue with wiring - the readings PCM gets will be off and it will get an error. The fact that you replaced the sensors and still get the same error confirms the wiring issue. You have to check the connectors and harnesses leading to the temp sensor.

Thank you for the reply. Im not the most hands on guy...what direction would you go to check this? Tools needed..etc? Again, thank you for the response.

Basic tools you'll need is the Multimeter (you need to measure voltage and continuity at the sensor). It would help to find a shop manual for your vehicle, so that you can follow the troubleshooting steps to measure input/output from the sensor.

No shop manual, but i can find something out there on the good ole inter webs....again. Thank you!!

Look at the sticky posts on this forum. There are links to PDF downloads there.