Mazda 2 - fuel gauge stuck on full

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Tue 14 Mar 2023 20:11
Mazda 2 - fuel gauge stuck on full - maz64

This is in a 2015 onwards model, digital display. It's showing full, and the predicted remaining range seems to tie in with that - pretty steady, just varies depending on the weight of my right foot.

This is following a very flat battery, for reasons I'm too embarrassed to go into, so various electronic things got lost/reset. I suspect the fuel gauge problem is a consequence of that - needs some sort of recalibration? Or else it's just a broken sensor, and the flat battery is a coincidence.

Any ideas/suggestions?

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Tue 14 Mar 2023 20:48
Mazda 2 - fuel gauge stuck on full - elekie&a/c doctor
I would disconnect the battery for 10 mins . Then let the system reboot . Probably got confused with a low voltage issue .
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Tue 14 Mar 2023 21:07
Mazda 2 - fuel gauge stuck on full - maz64

Thanks - will try that.

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Sat 18 Mar 2023 17:16
Mazda 2 - fuel gauge stuck on full - maz64

Well I put a new battery in this morning, with a gap of 10 mins after taking the old one out. Filled the tank to the brim, drove about 140 miles to Reading and back, and it's still showing full :(

Looks like I'll be calling a Mazda garage on Monday.

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Sat 18 Mar 2023 18:40
Mazda 2 - fuel gauge stuck on full - Andrew-T

Looks like I'll be calling a Mazda garage on Monday.

It's a digital display, but there must be a mechanical device of some sort in the tank. The ECU meters the use of fuel and calculates how many miles you might do before getting low; is that telling you anything ? If the 'float' device (whatever it is) is stuck at the top, it may need to be replaced, or should be able to be freed. Don't let any mechanic take you to the cleaners !

Does the gauge drop to zero with ignition off ?

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Sat 18 Mar 2023 19:05
Mazda 2 - fuel gauge stuck on full - maz64

The 'miles left in the tank' figure ties in with the tank being full, about 430-450.

I'm less inclined to think it's mechanical due to the fact this only started happening after I flattened the battery. And it's not impossible that it's still 'sorting itself out' after that event, and after changing the battery this morning. But of course I don't know for certain.

I'll leave it a bit longer before going to a garage, do more miles without refueling and see if it catches up. I made a note of the mileage after filling up so I know roughly how far I can go.

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Sat 18 Mar 2023 19:08
Mazda 2 - fuel gauge stuck on full - maz64

I should add that the battery went flat while we were abroad for a week, so it might be that something seized up during that period. But it's not unusual that I leave it a week between drives while I'm at home.

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Sat 18 Mar 2023 19:10
Mazda 2 - fuel gauge stuck on full - elekie&a/c doctor
If the range is reading correctly, then the level sensor in the tank is ok . I would do a few more miles to see what happens.
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Sat 18 Mar 2023 19:16
Mazda 2 - fuel gauge stuck on full - maz64

The range isn't reading correctly - it should drop as the tank drains. Apologies if I used the wrong terminology.

Edited by maz64 on 18/03/2023 at 19:17

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Sat 18 Mar 2023 19:19
Mazda 2 - fuel gauge stuck on full - maz64

BTW I've posed this question on the Mazdaforum website in case it's some Mazda2 specific 'feature'.

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