Crazy Temp Gauge

[General Mishap Co]

I have an '03 Yukon Denali with a strange problem that developed about 2 months ago. The temp gauge will quickly jump up past 200, sometimes maxing out into the red, but just for a second or two and then promptly back to normal. Often this will trigger a "Engine Overheated" message.
No indication under the hood of overheating(I've tested with a digital heat gun)
I've noticed that almost everytime this happens I'm braking to a stop, or turning right. I thought it may be the coolant temp sensor so I replaced it - no change. Then I noticed the coolant temp sensor wire was crimped and the plastic connector cracked, so I figured, here's the real problem. I replaced the connector and wire - no change.

Is it a bad gauge? Bad sensor? Bad BCM? Looking for ideas on where to go next.
..thanks

 

[Doubeleive]

intermittent problems can be a real pain because narrowing it down is hard, that being said I believe and I could be wrong that in order for the engine overheat to come on it would have to think there was a problem being sent from the sensor or ecm maybe. the cluster could be all fubar and should not make the engine overheat pop up, so I would most likely try replacing the temp sensor as a starting point, cheap and easy.

 

[Doubeleive]

I would also poke under the hood and check your battery cables and grounds and just give all wiring a good look over make sure there are no critter bites or wires sitting on anything rubbing the bottom and exposing bare wire. feel the wires and/or lift them up and inspect to be sure. a flashlight is handy for a good look.

 

[General Mishap Co]

I would also poke under the hood and check your battery cables and grounds and just give all wiring a good look over make sure there are no critter bites or wires sitting on anything rubbing the bottom and exposing bare wire. feel the wires and/or lift them up and inspect to be sure. a flashlight is handy for a good look.

Thanks for the suggestion, I'll check for wiring damage and grounds. Btw, I did replace the coolant temp sensor but there was no change.

 

[Doubeleive]

Thanks for the suggestion, I'll check for wiring damage and grounds. Btw, I did replace the coolant temp sensor but there was no change.

@rockola1971 any idea's

 

[Donal]

I have an '03 Yukon Denali with a strange problem that developed about 2 months ago. The temp gauge will quickly jump up past 200, sometimes maxing out into the red, but just for a second or two and then promptly back to normal. Often this will trigger a "Engine Overheated" message.
No indication under the hood of overheating(I've tested with a digital heat gun)
I've noticed that almost everytime this happens I'm braking to a stop, or turning right. I thought it may be the coolant temp sensor so I replaced it - no change. Then I noticed the coolant temp sensor wire was crimped and the plastic connector cracked, so I figured, here's the real problem. I replaced the connector and wire - no change.

Is it a bad gauge? Bad sensor? Bad BCM? Looking for ideas on where to go next.
..thanks

When the vehicle is first start for the day: the temperature needle should sweep to the left and go past 160 when key is rotated to run. After engine runs the needle should again sweep left and then register at 160. Needle should move to higher temperature as engine runs.

 

[Fless]

I wasn't aware that the NBS cluster gauges did sweeps when the ignition is turned on. I don't think mine does, but the Denali gauges might act differently.

As @Doubeleive noted it's not the gauge -- the needle position doesn't trigger any codes. Not sayin' the stepper motor for the gauge is good, but it's not the cause of the code. It sounds like an intermittent connection in the ECT sensor circuit.

For grins, remove the two connectors at the PCM and inspect for water migration and pin fitment. Water can get into them and wreaks havoc with the connections in the lower contacts.

 

[Doubeleive]

When the vehicle is first start for the day: the temperature needle should sweep to the left and go past 160 when key is rotated to run. After engine runs the needle should again sweep left and then register at 160. Needle should move to higher temperature as engine runs.

I think you have the wrong year in mind, that is a feature on the 2015+
a gauge sweep can be performed with a tech2

 

[Donal]

I think you have the wrong year in mind, that is a feature on the 2015+
a gauge sweep can be performed with a tech2

I am sure that you are correct.

 

[OR VietVet]

More Information for GM GENUINE 2134333

Did you use this temp sender? It calls for a specific wiring connector to be replaced at same time.