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fuel gauge on zero (red led)

88K views 145 replies 34 participants last post by  PhilLap 
#1 ·
The fuel gauge will not read above the red led on my car. I know there's fuel in it as I put some in yesterday.

I have disconnected the battery to try a reset but no joy.

It did this a couple of times in August, but been fine since and that was when the tank was brimmed and it worked after 10 miles or so.

I realise the float unit is housed with the fuel pump, but how to test it's that not the wiring?

Do I disconnect it and see if the gauge reads full, as they used to in the good old days?

I'm loathed to assume it's the sender as they are not cheap as it appears you have to buy the pump too. Pulling the pump out without a replacement seems uneconomic too.
 
#3 ·
So the Mini has two fuel level senders, so it's unlikely both are broken (esspecially as the fault has occurred after leaving the car a coupke of days in the garage - went in fine, came out not working).

I've used the on dash test menu and test 6.2 - Show value of Fuel gauge:
1= both senders OK, 2= sender failure, 3=ti signal implausible (no reading)

My result is 3.

Test 6.0 shows the car can read levels from both sides if the tank, but they differ greatly.

I wonder if that's the issue and if so what's the cure?
 
#6 ·
what was your fix. i've had a similar problem where driving down the road with 3/4 tank it suddenly goes to empty and all the lights and bing bong noises go off then it goes back up to the level. it done this a couple of times about a month ago. i went out to my car this morning know last night i parked up with 1/4 tank and it says full tank, i drove down the road and the gauge was descending but only went to 3/4. I turned the car off and its back to full tank again. I just put 25 litres in the car so i do now have a full tank but I was wondering if anyone can shed light / help with mine and what your fix was as it may help me with my problem
 
#9 ·
Me too. 3/4 full when brimmed for the last 2 years or so, and last weekend started showing empty. Going to try disconnect the battery (though Ive no faith in this) and check our the test menus too. Unless you can enlighten me, ill be breaking out the multimeter this evening and checking if the sender units are getting voltage.


Step 1 though... check the fuses. :big_grin:
 
#15 ·
I'm with JohnnyC on this one. The whole point of a forum is to share, why is this such a big secret? How would you have liked it if people had replied to your request for help with "I know how to fix your problem but I'm not going to tell you"...?

Fortunately, my fuel gauge works so I'm not reliant on your knowledge but I think you're missing the point of this place.
 
#18 ·
Thats why helpped all 3 people via pm who asked me to sort it? Get your facts right before jumping on someone elses band wagon. Its not as simple as writing some instructions.

Pity it cost me over £150 to find it out myself wehen no one could be bothered to help me, much like my requests to help with the windows and roof operation on my car.
 
#16 ·
So a bit of info on what ive found out since. I did a drive in the car there with the diagnostic mode running on the fuel levels. The left level is fluctuating (fuel sloshing about), but the right level is set in stone at 22 liters. Ive a few theorys. Either a wire is snagged, and being grounded/not grounded somewhere, or the something's up with the sensor itself. Unfortunately I need a multimeter to check out both (other than visually looking) so ive a few days wait before I can get my hands on one.

Pulled up the carpet a bit under the back seats (passenger side) and I can see the wiring going into the pump, but nothing suspicious looking. Im going to open up the right inspection port to see if anything is loose there, and if not ill try taking off a few plastic panels to chase the wires a bit more. Beyond that I really want to get a multimeter so I can A) check for continuity and voltage at the points, and B) pull out the fuel sender unit and check its resistance.
 
#17 ·
Pulled up the carpet a bit under the back seats (passenger side) and I can see the wiring going into the pump, but nothing suspicious looking. Im going to open up the right inspection port to see if anything is loose there, and if not ill try taking off a few plastic panels to chase the wires a bit more. Beyond that I really want to get a multimeter so I can A) check for continuity and voltage at the points, and B) pull out the fuel sender unit and check its resistance.
Just so you know, there's a second fuel level sender on the drivers side too on the fuel filter housing.

BMW did tell me that one is for the high level, and the other for the low level, but personally I'd take that with a pince of salt.

This is with the fuel pump removed, two fuel lines and an electrical connection for the fuel level sender.


I do know that if either fuel level sender is broken, then the fuel guage doesn't work, and the 'range' on the computer shows as '---'.

However, as your test shows that the car does know about the fuel levels then this is unlikely to be the cause of your problem.
 
#29 ·
Em... so back on topic. K3fus may have been burned in the past, but he's been a nice help to me. Ive no problem documenting everything I do so hello future mini owners. We're here to help.


Anyways, I opened up the 2 inspection hatches in the back to reveal the fuel pump, and the fuel filter. The fuel filter (drivers side) only has a fuel line going into it so I left it alone, unless there's more wiring inside the tank (though this seems wrong to me). I see what you see in this video at 2.45:
youtube.com/watch?v=rCppUQfNZQQ (cant post URLs yet)

So I abandoned that inspection hatch, and opened up the passenger side hatch to reveal the fuel pump and its wiring. This looks to be the wiring that I followed from the rear footwell, underneath the carpet. Only thing I can say is, 1 wire looks shoddy. See here:


You can see the rubber bung is perished, and loose from the connector. Im wondering has water gotten in and corroded it. Again, need to get my multimeter out. There also seems to be a little nick in the wire too. Need to get my hands on a wiring diagram or something to clue myself in.


Big question I have is, where are the 2 sensors? Diagnostics are saying the right fuel level sensor is registering the max 22 liters, but I though this was located where the fuel filter hatch is. I assume the left sensor is in with the fuel pump.

Oh, and I pulled out the battery for a few minutes, popped it back in, and now my 6.2 diagnostics is saying error code 2. 2= sender failure
 
#30 ·
JohnnyC, is that picture of the 2nd fuel sender unit what is underneath the fuel filter?

Just found this guide:
pelicanparts.com/techarticles/MINI/17-FUEL-Fuel_Pump_and_Filter_Replacement/17-FUEL-Fuel_Pump_and_Filter_Replacement.htm

Still cant post links
 
#31 ·
JohnnyC, is that picture of the 2nd fuel sender unit what is underneath the fuel filter?
My pic above is the of the fuel pump connections.

I have to admit, when I changed my fuel filter several years ago, I never noticed a fuel level sender. As the fuel filter housing is only pulled up to change the filter, it's not fully removed.

But this diagram shows the sender on the fuel filter housing
RealOEM.com - Online BMW Parts Catalog

Also, I have assumed that the fuel level from the fuel filter housing travels along the wiring that goes to the fuel pump. Because there's no electrical connections going into the top of the fuel filter housing.
 
#33 ·
Multimeter said the shoddy wiring at least has continuity through the block. The rubber bungs stop me from getting a reading while its all connected, and wasnt too sure was there much point disconnecting it and measuring since it might just error out anyways.

From the look of the wiring, the middle brown and blue/white wires are power and earth, while the other sets of 2 are probably the fuel sender unit points. The top two (left most in the car) gave me a slightly varying resistance reading. Which the bottom 2 (right most in the car) gave me an open circuit. I suspect this is the cause for the solid 22ltrs in the right tank. The reading is sending back infinite resistance.

 
#35 ·
Quick update on this. The 2 pins im measuring are the left side sender unit. The middle 2 are power and ground. The last 2 are the right side sender unit resistance - They're giving me an open circuit when I measure resistance.

I pulled out the fuel filter side of the fuel system and got a look in at the wiring. The good news is, the fuel sender unit works, and I can read a varying resistance on the unit itself. So I opened up the left side unit (where the fuel pump is) and found the connector from the right unit over to the left (2 wires, black and green). I have continuity between the connector and the top of the fuel pump (pictured below), but I dont have any resistance across the 2 pins inside the fuel tank (black and green wires I mentioned). I'm making the assumption now that the fault is in the wiring between the filter unit and the connector under the fuel pump unit.

Will keep ye posted.
 
#36 ·
If the gauge is stuck on Red LED thats caused by wiring not the sender or sensor etc.

The most common issue is the corrosion with wiring get underneath the back seat .

Remove the round cover of the PASSENGER side Sender unit Check the wiring through .

You will have to remove the bottom interior trim .(The long plastic one from back to front)

Follow the wiring which goes underneath the car immediately below the sender unit before goes back in behind the cover you removed.

Check the wiring there because this is caused by a wire corroded possibly touching the chassis causing short circuit which seems like a sender sensor issue..its not.

Once the wire is fixed turn the ignition off replug the sender connector then turn the engine on.

It's important because the vehicle registered as the connector unplugged and carry on showing RED.

Once you plug in back in and turn it on and off BINGO the gauge is back to normal.

This is 99 put of 100 times is the problem.
 
#38 ·
I had the same problem and it was corrosion in the wiring under the passenger seat, please see my video with the fix.

Sorry can’t post link for a while I need 15 posts, please pm me for link.
Any chance of the link please?
We've got a code 3 but know there is 46 litres in the tank [emoji53][emoji53]
Traced the wiring under the rear seat but no visible damage.

Sent from my SM-G935F using Tapatalk
 
#46 ·
Hey does any one have the fix for this. Gauge stopped working overnight. Car had 3/4 tank full and now showing as stuck on red light and mpg showing ----
I have changed one sensor in the back, however i am not sure if the change the other one. when plugged into the computer at the garage the error is shows TANK LEVER SENSOR 2

any ideas on a further fix for this? thanks everyone
 
#48 ·
OK, hi everybody, just thought i would post my findings after scouring the internet and talking to bmw mini and having no luck whatsoever. so here is what i found, under the rear passenger seat remove the panel, remove plug from fuel pump, in front of the panel there is the floor carper that comes up and under the rear seat, pull that back and there is a rubber bung with a cable going through, pull this out and with a bit of tugging the cable will pull through, i found a corroded wire by pulling on each of the thin wires and one of them just snapped off, cut back a little then resolder a new wire to both cut ends, replace everything back to normal and hey presto, fuel gauge now working, this saved me paying out for a new fuel pump, hope this helps anyone out there, if you cant do it yourself, which i will say its a little tricky, then explain to a good auto electrician and he will fix it for you. this is what forums are for and i hope i have helped at least one person today.
 
#53 ·
I haven't done a system diagnosis check ..(don't know how to)..can you tell me how..and codes? Thanks.
Had the problem 4 months ago 3 segments.showing .however ran out of fuel..when filled still 3 segments.
Tested gauge op with separate tank units ok.. fitted them ..fuel gauge accurate. Today fault reoccured..tank brimmed ..3 segments. Ran for 50 miles gauge empty pump warning illuminated.
 
#57 · (Edited)
OK , Can I sum up what I think I've gathered from this.... the drivers side sensor measures the bottom half of the tank, the passenger side measures the top half ? , so if (6.0) shows 180250 , you'd expect the 180 to drop to 0 when you hit half a tank ? Which would make sense as (6.1) just adds the 2 together 180 +250 = 430. (6.2) shows 000 , which I guess means 3 blobs.(signal illegible) . I've checked the 3 spliced earth connections behind the passenger seat , they're OK , but I snipped and re-soldered them anyway to be sure.... so if 180 gradually drops to zero then 250 starts dropping, the sensors must be OK ? so why doesn't the gauge work if the sensors are ok. dodgy gauge ?
 
#58 · (Edited)
So I took it for a spin , now (6.0) reads 177250 ..... so that makes sense. Perhaps 250 is too high ? Maybe once I get down to half a tank , and the 250 starts dropping, the gauge will start working again. The weird thing is (6.2) used to be 000 ,which I took to mean 3 , but it now says 014 , so that's confused me.
 
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