How far out of range is OK for Coolant Temp Sensor?

[GrammaCar]

Hey, guys.

I'm still fiddling around with my Code 22.

I tested my installed Coolant Temp Sensor to check if the resistance was within spec. My Haynes manual says it should be 5000 - 5600 ohms cold and 900 to 1000 ohms warmed up.

When tested cold, I got 6000 ohms (weather is about 57 degrees out right now) and after about 6 or 8 minutes of running it had dropped to 750 ohms (and was still dropping, but very slowly). Does that sound OK to you guys?

I'm used to checking for continuity and just testing for open or shorted, I'm not very experienced with specific resistance readings outside of a few capacitors here and there.

[GrammaCar]

Yeah, that's the sensor I was working with. The two-prong next to the thermostat. If it's supposed to be 20,000/2,500 than it's definitely way out of whack.

I did at one time have the Sender and Sensor confused, but I got that straightened out today.

Thanks for the info.

[Kwagon2]

Hi
I had to rethink the info I was giving you as there were a number of changes to the Turbo EFI setup between '84 and '85
most of it was around the info that the Logic module used. It's been a while since I've had my hands on a Turbo I car. I do need to correct myself on the fan control as for '84 the fan is still controlled by a radiator tank mounted control switch as in previous years. In '85 for sure the fan control was incorporated into the logic module function. The code 22 is telling you that there is a problem in the Engine coolant temperature sensing circuit. The sensors are still available so getting another to try should not be a problem just keep in mind that '84 is unique, that I'm sure of....

[K-CAR_WAGON]

5290 to 5610 @ 77 degrees F; it would be a bit higher at 57 degrees F (maybe about 800 ohms higher if the sensor is linear). I think your cold temp measurement is probably reasonable.

Not sure about the hot measurement.

See link belows (which also include some expected voltages)
http://minimopar.knizefamily.net/fault/code22-1984.html
http://minimopar.knizefamily.net/ecu/co ... mp_se.html

[GrammaCar]

So I tested the sensor and everything was within spec. Then the warning light quit coming on. I think it must have just been a loose connection or something.

I guess I'm all set now.

Thanks for the help, everybody!