I have a 03 Yukon XL that has a 6.0L, the oil pressure guage started acting funny a couple of days ago, it would peg at 80psi while at idle but when the key was off it would only drop to 40 on the guage. Then it started going well past 80 and with the key off it would fall to 60. Now it is pegged all the way to the right and with the key off it falls back to 80.

Has anyone ever had this happen??? What could cause this and what is the fix??

 

Either the stepper motor for the oil pressure gauge in the cluster is bad which their have been A LOT of issues with the clusters on the 2003s or the oil pressure sending unit itself.


Reading your description again sounds more like it would be in the instrument cluster itself but don't quote me on that, would have to do some diagnosing to pinpoint the problem for sure.

 

Is there a way to hook up a secondary oil pressure guage to mount in the vehicle? That is if the sending unit is good?

 

What you've described is a defective stepper motor. There are people on eBay who do repairs for those (most of the time it is NOT just a parts swap, stuff is soldered in).

I recommend this guy:
Silverado Sierra Tahoe Suburban Yukon Avalanche Hummer Truck items in INSTRUMENT CLUSTER SPEEDOMETER SALES REPAIR GAUGES ESCALADE store on eBay!

The sending unit does not affect the needle position with the key switched off. When the stepper goes bad the zero point goes bad, therefore the needle will go to random positions when off and move clockwise when the power is on.

 

It could be an oil sending unit bad, try putting a mechanical gauge on and see what it shows before you start chasing problems you don't have.

 

I have been chasing this problem in my uncles truck. what dose urs do if you cycle the switch on/off,on/off,on/off,on/off with out starting the motor, his will actually work itself back to 0 while off and normal reading for a little bit while running then works its way back to high while running and 40+ when off.

 

If you have a high mileage truck (90000+) then it more than likely is the stepper motor, after the oil pressure goes, then the temp guage, and then it is a tossup--speedo, or battery is next. Confirm it is not the oil pressure sending unit--cheapest fix--then google cluster repairs in you area for a fix. Usually $100-150.00. When mine went I had several local and made an appointment, drove over and less than two hours later was driving home.