rossinvrland

On the way to work this morning, my rad fans turned on and didn't turn off again. Somewhere around the same time, my temp gauge showed a cold engine. By this time, I had been driving for 40 minutes. When I drove home after work, the problem was completely nonexistent. Anyone run into something like this before?

holeshot

Had the same thing happened to me 2 times. As soon as it happened, I turned off the engine and started again, then it has disapeared. Second time I had the chek engine light on with a code (don't remember). I have an appointment on jan. 14 for a diag.

After a couple drive cycle it has turned off.

CharlesS

This problem will happen when communications with the coolant temperature sensor are lost due to a bad connection (dirty contacts or loose connector); the ECM turns the fan on as a default to make sure the engine stays cool. This is also a test to ensure the electric fan and relay are functional...
The fact that the engine temperature gauge acted up too... confirms this....
Check the coolant temperature sensor harness connector before going to the dealer.

holeshot

OBDII Code P0116 JEEP - Engine Coolant Temperature Sensor Performance | HelpForCars.net

ronjenx

I was thinking this was the case, but couldn't find it in any of the manuals.

Do you have a source?

(I would go out and pull the cts harness to see what happens, but I don't have an electric fan in my JK.)

holeshot

every JK's have electric fan

ronjenx

Well, OK, I have one in the HVAC module, but that's the only electric fan on mine.

holeshot

I never seen a jk with a radiator fan clutch...

holeshot

My jeep is at the dealer now, the advisor told me he ordered an ECT sensor, will know more when I'll pick it up tonight.

holeshot

ok I got it back today, They replaced the ECT and did an update to the pcm or ecm? it is supposed to fix the issue.