Code 118 ECT Sensor - Can't find problem

[StevenC]

Hi everybody - I'm new to the board and wanted to say thanks in advance for everybody reading the post and offering help! I've had a 98 camaro since about October 15ish, 1997 when they first started rolling out. I've had trouble off and on with it, and I've got an engine light on right now. Here goes:

The engine light is for a code 118, it's an engine coolant temperature (ect) sensor. It reads excessively cold; I think the factory's service manual says it has to be under -34 for it to read this and it hasn't hit that cold all year in Nashville (where I'm at). I checked it the other day when ambient temp was about 60 and it gave the code.

I disconnected the connecter from the sensor and put the connector to ground; the temp. gauge on the dash deflected full to the right. I'm presuming that means the connector, wiring, and gauge work. It's a trick the Haynes manual says to do to check on the connector/wiring/gauge. I've also checked the resistance on the ECT sensor when cold and it's very high 2KOhms+ and only about 100 Ohms when warm - which is the range it should be.

So my problem is this: If the sensor, connector, wiring, and gauge all test to be ok, where is the problem? Am I missing something? Has anyone else had this problem? Many thanks in advance for the help! Let's try and get my ride rolling again! :(

[Marty85]

There are two temperature sensors for v-6's. One is located on the cylinder head and that one is for the temperature guage only. The temperature sensor that the computer actually uses is usually in close proximity to where the thermostat sits. I know on 3.4's its right next to it but im not sure about 3.8's. If your temperature guage works ok in the dash and it still throws the code its more than likely the sensor that the computer itself uses.

[StevenC]

Hey Marty, thanks for the reply. Unfortunately, on the 3.8L it has a dual-purpose temp sensor that feeds both PCM & gauge. Otherwise, that would sound like a great way to fix this problem. I'm probably going to succumb and take it into the Chevy dealer.
I had my water pump go out recently and this problem cropped up right before then. When it went out, it let loose a flood of water across the front of the engine and I'm presuming something happened to it then. The belt slipped off and took out the tensioner, and the temp sensor on the 3.8's lies right next to the belt so it might have whacked it hard enough to skew readings or so. We'll see. Thanks again.