Code P0118 Temperature Circuit High Output

My 98 Saturn SC2 DOHC "Check Engine Light" is on and code reads P0118 Temperature Circuit High Output. I've changed the thermosat and engine coolant temperature sensor and cleared the "CEL" with scanner but the "CEL" reappears within 5 minutes and so does the P0118 code. What should I be looking for or do to fix this problems? Can anyone help?

You might need to replace the temp sending unit plug. They are known to corrode. I'm not sure where to get one these days as I've always bought them from Saturn dealers.

Correct me if I am wrong. Is the "Temperture Sending Unit Plug" one in the same as the "Engine Coolant Temperature Sensor"? If so, it was replaced with the an aftermarket brass type as recommended by many along with the thermostat which was the culprit for causing engine to overheat in heavy traffic in the first place. Two things, should I replace the temperature unit (sensor) with an OEM version and is there more than one temperature sensor on my 98 SC 2 DOHC? If so, where can it be located? BTW, thank you for the quick reply Cat Fuzz.

What I meant was, you need to replace the wiring connector that goes to the ECTS. I don't remember when but early Saturns had two temp sensors. One was just for the dash gauge and has only one wire coming from it. The other is for the computer and has two wires. The one with two wires is the important one. Yours might be of a year that there is only one.

If you have recently replaced the ECTS with a brass one, it is unlikely to be bad.

Okay, that makes sense. You are right about the wiring connector, it was corroded. Will be replacing it on Thursday. Also, I found that I only have one ECTS with the two wires so you are right again. I'm crossing my fingers and hope by replacing the connector it will fix the problem (Code P0118). I will let you know what happens. Again, thank you for all the information Cat Fuzz.

It was the connector plug. All fixed and no code. You were great help CF, Thanks.

Cool. :cool: