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Temp Gauge down, Check Engine Light ON!

theblackXJ

NAXJA Forum User
Location
Oregon
I have looked over the forum for a while and I can't answer my question. I am a new user to the forum, but the forum is not new to me. I went wheeling last night, in some mud, but mostly hill climbs. When I was almost home, I noticed the temp gauge go dead and then immediatly after, the Check engine light came on. After I parked it in my driveway I tried to start it again and it wouldnt start. I am aware of the two sensors, one for the gauge and one for engine management. I assumed it was the coolant temperature sensor, but wouldn't the gauge on the dash still work if it was? If it was the sensor going to the gauge, would the check engine light still come one? If anyone could give me some advice on this it would be great! I need my rig back!
 
I had the same thing happen on my 1997 Cherokee 4.0 except the engine check light did not come. It was the thermostat and it was stuck open, the engine couldn't warm up to temperature.
 
Yeah, it will start when the engine is cold. The temp was normal just before it occurred, and instantaneously went to below zero. The check engine light came on immediatly after that.
 
Does anyone know if the 1997 only came with one coolent temperature sensor, the one in the Thermostat housing? Cause I looked right where it should be and I couldn't find the sending unit that goes to the gauge?
 
Mine did the same thing(97) and I changed the t-stat. It was good for a while, and then recently the temp sensor took a crap, so I changed it and it is like new now. I would just get the sensor and t-stat, flush the radiator and heater core and you should be good.
 
Thanks for the help. I guess I was just getting to that conclusion that there was just one sensor. It is not unpluged, but worth a try! That definately solves my confusion, I can get started on some parts now. Thanks again.
 
The sender wire, if disconnected should make the gage read zero.

When grounded, it should read all the way high. So ground it and see if the gage works. Otherwise it is a gage problem.

For the CEL use a code checker. If you don't have one, ... now might be a good time to get one ($100). (I have a 97 XJ also and have used the tool many times already.)
 
hmmm...The wire is connected to the existing Sensor, and the gauge does read zero. Does a faulty sensor usually read all the way high if it is grounded properly. Maybe since I was in the mud, I should be looking for a short, or maybe one of the grounds is loose? I have a new sensor, and I haven't put it in yet. I don't have my own code checker either, I should probably get one, I'm sure I would get my $ out of it.
 
On the code checker (ha..LOL) you will use it, you own a Jeep.

It is also used on all other brands as well. (But you can go to AutoZone, Kragen's etc. and borrow theirs.)

What I meant is to take the wire off and ground it...it should read HIGH.
 
Oh, yeah take the wire off, that makes sense. I'll try that. I know I would use the code checker, I've already made use of AutoZone several times as well though.
 
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