87tunedport

i need to replace the coolant temp sensor that screws into my thermostat housing (for the ECM not the gauge) i have gone through 2 parts store sensors already because they keep triggering the SES code 15 high resistance.

i ohm tested the sensors in boiling water and at 220 the sensors ohm was 200. according to service manual that i got in another thread they are supposed to go down to 185. anybody know where i can get an original one?
i tried ebay, rockauto, amazon and keep getting the sensors i have already tried

my car is an 86 Firebird Trans Am with 5.0 carburetor automatic

sofakingdom

iTrader: (1)

That's not your problem.

You get that code when the resistance doesn't go down to a point that indicates a temp of about 120° or so. ANY engine, under ANY circumstances, in AMY outdoor temp that a gasoline motor will run at, should reach a temp of around that, in 10 minutes or so of running. If the ECM doesn't see it reach 120° (or whatever the exact # is... I forget) within 10 minutes, it assumes something is fornicated. The resistance it's looking for is something like 1.5k ohms.

The difference between 200 and 185 ohms at 220° is MUCH too fine a detail for that ECM to even notice.

I'd suggest checking the wiring instead. Sounds like you have a broken wire somewhere. Most likely, at the pigtail end.

Ja85z28

OP,

There's lots of cars being parted out in the Classified "Parts For Sale" section.

Good luck

sofakingdom

iTrader: (1)

Looks to me like you could put a brand-new OEM "perfect" sensor in there every day, and twice on Sundays just for good measure, but still get code 15 after it's been running for 10 minutes or so, EVERY TIME.

The problem is not the sensor. You can verify this for yourself quite easily: take one of your "bad" ones; remove the electric connector part of it, with little enough sodomization that you can still plug the harness into it; buy a 180 ohm (205° or whatever) resistor; hook that up to it; I'll bet MONEY - a NICKEL - it'll STILL give you the "high resistance" error. Hell I'll go all in, I'll even bet you A DIME ($0.10). That's how sure I am.

Your problem isn't the [spock]sen--SORE[/spock]. You're barking up the wrong tree.

87tunedport

your right sofa, i have a wiring problem or a problem with the ECM. i have a LOADpro ordered along with a service manual. all you guys suggested i get those.

i did some testing with my DVOM but i dont think its of any importance that will tell me what my problem is