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jorygun 09-09-2021 10:03 AM

p32 8.1 erratic fuel gauge
My fuel gauge is inconsistent. When I first turn the ignition to ON, the gauge either snaps to 0 and floats to correct reading, or snaps to about 1/3 full and then floats to pegged at top (assuming the tank is has plenty of fuel). 3 times out of 4 it pegs. If it pegs, I can turn the ignition OFF for 10 seconds and then back ON again for another chance.

If it pegs, it seems to be reporting actual + 1/2 tank or so, so as I get low on fuel, it will decline to FULL and below.If it doesn't peg, then it seems to be accurate until I shut off the engine again.

Pegging indicates an open or high R in the sender line, but it's strange it doesn't always do it, and makes its choice at startup. And more mysterious, the "information message" in the speedometer area seems to report the correct miles-to-empty in any event, so I've started using that instead of the gas gauge. I'm guessing a bad contact on a relay somewhere. Anyone have any ideas??

(NB: I've had rats chew through engine computer wiring twice. So could be something I missed in there.)

Ultra RV Products 09-09-2021 10:41 AM

It is quite possible it is the gauge stepper motor itself. To isolate the gauge from the sender, you can run the gauge diagnostic test to see if it sweeps properly. Hold the “mode” button down for approx 10 seconds and release, you will enter a new menu. Using the trip button to scroll down go to cluster diagnostics and leave that highlighted, it will proceed to a new menu. Scroll down to gauge test and leave it highlighted. It will initiate a self test of each gauge, when it gets to the fuel gauge and it still is acting erratic, you need a new stepper motor. We do this repair so if needed, just contact us.

Isaac-1 09-09-2021 04:52 PM

If you have an OBDII scanner or smart gauge chances are you can read of the raw sensor value and this will help tell if the problem is in the sender or the gauge console.

jorygun 09-10-2021 11:12 AM

Holy smoke! Had no idea this 2005 unit was so smart! And you nailed it. When I do the test function, at 0 the guage points to 1/3; at 50% it's at Full; and at 100% it's pegged. Will send a PM about how to proceed.

SmilingSam 09-19-2021 06:57 AM

Whats worse, erratic gauge or trip computer saying I have 500+ miles to empty when gauge is saying 1/4 ?? ;)

Gauge of course was correct, trip computer just plain STUPID, but at least it got the Covid-19 vaccine !!!! ;)

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