2000 jeep grand cherokee

[jeep58]

The check gauges light comes on and goes out, jeep runs good why does this happen? I replaced computer last year and everything was working fine.

 

[atikovi]

Temperature high, oil pressure low, fuel level low.

 

[Driz]

Check your coolant temp on gauge. Those things have a 2 speed fan and are managed by a resistor block or some sort of relay module down on the pax side frame rail in front of the engine. They are not expensive $40ish and notorious for going wacky but not fully failing. There's good info on YouTube on it someplace. Dont just run out and buy one but keep it in mind as they are a well known issue. Iirc you check with a multimeter.
Check the fan motor itself that both hi and low are working.. the procedures are on the net someplace.

 

[jeep58]

Well I replaced the fan and the cooling relay, what happen is I was towing the boat after I got the boat into the driveway and shut down I herd a loud pop, turn out that the upper rad hose split right down the center and coolant was all over the place, replaced hose and rad cap. The engine at idle will go a little above 210 the the fan will kick on cool it down and cycle off. I checked for codes none and no pending codes. Jeep runs good I can try to check the rad with a inferred thermometer but they are to accurate.

 

[Driz]

Well I replaced the fan and the cooling relay, what happen is I was towing the boat after I got the boat into the driveway and shut down I herd a loud pop, turn out that the upper rad hose split right down the center and coolant was all over the place, replaced hose and rad cap. The engine at idle will go a little above 210 the the fan will kick on cool it down and cycle off. I checked for codes none and no pending codes. Jeep runs good I can try to check the rad with a inferred thermometer but they are to accurate




Overpressure = get a new radiator cap. . Try that first then the stat. I'll bet it's the rad cap though since it got so pressurized.

 

[jeep58]

I did replace the radiator cap with a new one, I is running ok so far I disconnected the battery to reset the computer.

 

[Anon9283]

4.0 or 4.7? The 4.7 doesn't like to be overheated. Hope it's ok

 

[jeep58]

It is the 4.0 engine very strong, maybe the coolant temp sensor that controls the pcm when to turn fan on and off ? Engine volts checked with meter are good, oil pressure gauge not erratic, Got me baffled on this one!

 

[jeep58]

Ok so when the jeep sits over night the check engine light comes with check gauges, if I disconnect battery it will reset the computer but same thing happens when it sits for awhile so I am thing that the ecm is bad, I changed it out (ecm) a year or so with a I thing rebuilt one, I do not have the paper work on it any more so I screwed up on that one. When the check gauge light come on the check engine light comes on , the power windows do not work the a/c and the cooling fan does not work, if I rest the ecm by disconnected the battery for a while then reconnect battery back up check engine and gauge light go out and everything works,, Bad ECM maybe? Very frustrating !!!!!!!!!!!!!!