Would tearing the wiring harness apart be worthwhile to trace those 2 wires all the way back? I think its pretty unlikely that the wires themself are the problems though.

I guess its possible for air to be in the system. I just put a new cylinder head on and filled the system back up.

 

How is the shotgun approach working for ya...replace without testing. Its your $65 plus programming costs. good luck with that.

If it was me, I would verify the wiring is ok first. The wiring is 15 years old. Its a 10 minute test.

 

jumper the wires together at the switch, then key on. If that induces a po117 all the wiring and pcm is ok. If you can't induce a p0117 but have 5volts on the yellow wire the grd wire is open.

all the head gasket stuff...air in the system etc won't induce a p0118. 117/118 are all logic tests for the pcm and wiring.

 

I will test for 5 volts on the yellow wire with the key on tonight. What do you mean jump wires together at the switch? What switch? Sorry I am not following what you mean.

 

sorry, jump the terminals together at the ect sensor connector. so yellow and brown wires

 

Got 5 volts on the yellow wire. I put a paper clip in the plug as a jumper and started the car. No p0117 and the temp gage did the exact same thing.

 

Well, I guess tech2 is correct. If you jumpered full voltage to the switch leg, and if it were a complete circuit, you should have pegged the temp guage. I'd first before tearing the wire harness apart, is to use an electrical cleaner, and spray the connections well.

 

I'll tear into the wiring harness tomorrow night. Sounds like its more than likely the ecm though. Whats it take to fix that? If that doesnt work I am done with this damn car.

 

why why why do you still think its ecm? the ecm reads its voltage signal from the 5volt ref side of the circuit not the grd side.

 

Obviously I dont no lol. Where does the ground side go then?