We've had our Enclave for 11 months. We are the second owners and got it with low miles (20,000) from a dealership. Hopped in to go somewhere and I noticed that the fuel gauge was reading about 1/8 tank. I knew we were driving for a while to I put in 4 gallons from our fuel cans used to service the riding mower. Anyway, needle didn't move up. Engine started and runs fine. After a while the message center declares --- mile range and the Check Engine Light is illuminated. I checked the code to be P0463 (overly high voltage seen from sending unit). So, lost likely it's the sending unit within in the tank, on the pump module that will need to be replaced.

Darn, I had bought this vehicle to treat myself and wife a little so that I wouldn't have to find myself working on it for a few years, but nope, I'll be back to my trusty ways on it soon. I did do this type of work before on our Chevy '05 Trailblazer which means: drain and drop the tank, open up the top to fish out the pump assembly and replace the part (about $80 from O'Reilly's).

I shall report back on this when and after I get this job done, but for now it does run and operate fine.

If this should happen to you, first go and fill up your tank to know it's FULL, then reset one of the odometers to start counting mileage. Its around 300 miles when I start to look for another fill up. But a bit of a bother to count mileage like I do with my /92 Buick Rivera. Keep those classics going I say!

Best of luck to you and feel free to reach out if you are in need of help.

Christopher B.

Update from Sep 5, 2023: UPDATE: September 5, 2023. I found the original problem after buying a new Fuel tank level sensor and also a new pump. It turns out that the WIRING HARNESS was the problem as there was one wire that was broken. This wire is part of the sensor signal. I should mention that the harness section where it plugs into the underside of the body seemed to have taken on some rough abuse, either from the road/debris or there was a mouse critter nibbling on the loom and wire. What makes me think that it was NOT a mouse is that the loom did have the typical signs of nibbling. It was more of a crushed damage. I also noticed that there was another wire that had a damaged insulator and the wire was corroding green. This could have been the way that the level sensor wire went. If there is ever some slight damage due to debris or even a mechanic needle probing, this leaves the wire prone to get water (especially salt water) in there to eventually corrode and break the connection. Please check the integrity of your harness! After I performed a good clean and crimp of the broken wire, I wrapped it up with self-sealing silicone tape and even used more loom hose to keep the elements out. I even treated the ugly other wire this way.

My fuel gauge now reads normally and I think I've got it solved. It would have saved money to find this first but at least I'm back in action with a spare pump now.

Best of luck out there!

Christopher B.