Fuel gauge issue?

2004 BUICK LESABRE

198,000 MILES • V6 • 2WD • AUTOMATIC

BHAMDOC1973

MEMBER
2,007 POSTS
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Noticed it was on empty with the warning light lit, then went to start it again and it showed full. Read online as it being a common issue with gauge step motor or the fuel tank leveling unit. How can i tell which it is? Everything else in the cluster works. Looked at the digital part of dash and it matches the gauge. While driving gauges fluctuate, all of a sudden goes to 1/2 and range reads 259 when all way on full reads 415 miles left. How can i determine if it's a fuel gauge issue or the leveling in tank? Not sure whether the needle controls the range or the digital tells the needle to move.

Sep 29, 2022 at 6:45 PM

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STRAILER

AUTOMOTIVE REPAIR CONTRIBUTOR
54,180 POSTS

The fact that the digital part of dash and it matches the gauge tells us the gauge is working correctly. This means the fuel level sender inside the tank is bad, which is common as well, but to be sure we should do a CAN scan to see what comes up. You can get a CAN scanner (Controller Area Network) from Amazon for about $36.00.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Amazon CAN scanner link for about $35.00.

https://amzn.to/3R9lJ60

Here is how to change the sender out in case you need it. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.

Images (Click to enlarge)

Sep 30, 2022 at 10:04 AM

BHAMDOC1973

MEMBER
2,007 POSTS

Replaced pump assembly and all is good. Thanks for your help.

Oct 1, 2022 at 4:43 PM