Sub fuel tank light issues

[Pete's GU3]

Here we go again , now i have the light come on all of a sudden and i cant access the fuel , i tried to battery disconnect but that didnt last long it came back on . i ll do the battery earth lead and see if that is connected properly hopefully that works , if not ill try the one andy said about something behind the air con under dash somewhere ...see how i go

[AB]

Yeah try that Peter if no success come back and let us know.

I'm sure between us all we can come up with other trial and error suggestions.

[Pete's GU3]

Mate its just standard all the way , i looked at the fuses under the dash and under the bonnet , im guessing if they're not black or broken through the middle they should be ok ...its not an urgent fix right now i may wait till the next service and get them to do it , i cant really tell whats going on in there...

[Timbo]

Sub tank light issues for me were solved when I made a new earth point on the chassis and fitted a new earth strap. Give it a whirl.

[Nissan Kid]

Hey mate....
Currently having the same issue with my old mans 4.8 gu. We took it into Nissan and they had it for a day and said they would just put a new earth to the tank. Well that worked for a few hours and cost 180$.

They now currently have the patrol and have had since Monday and are now saying it is a power feed to the pump which is causing the problem. They said they will still need it tomorrow to fix it. They spent all of today finding the problem so hopefully they will sort it all out.

I know it may be a costly thing but you may have to take it to Nissan. If I can get them to tell me the exact problem I'll post it up.

[Pete's GU3]

Thanks for feedback ....keep us posted !!!!!!!!!!!!

[Pete's GU3]

I'll have a crack at it on the weekend , might run it past the workshop at the council {garbo}, couple of diesel mechanics in there ....

[Pete's GU3]

FIXED IT . FYI , I disconnected the battery , followed the earth cable which is the negative one down to the side of the battery housing unsrcewed the nut , took off the lead from the body gave it a good clean, as it was greasy and black also gave it a light sand, put everything back together again { no parts left over lol }turned her over and with my eye on the subtank light .......it went off !!!!!!!!!!!!..yessssssssss...pressed the sub tank button and drained all the fuel across ....so far so good ...about time i could fix something for free........also i didn't have to key in any pin for the radio which was good cos i didn't have one...

[AB]

Well done mate, mustve just built up some grit or something.

Good stuff!

[patch697]

FIXED IT . FYI , I disconnected the battery , followed the earth cable which is the negative one down to the side of the battery housing unsrcewed the nut , took off the lead from the body gave it a good clean, as it was greasy and black also gave it a light sand, put everything back together again { no parts left over lol }turned her over and with my eye on the subtank light .......it went off !!!!!!!!!!!!..yessssssssss...pressed the sub tank button and drained all the fuel across ....so far so good ...about time i could fix something for free........also i didn't have to key in any pin for the radio which was good cos i didn't have one...

Top stuff well done mate.... Do you have that code now? if not ring Nissan with you VIN No thay will give to you over the phone (at least thay did for me a few times now)

[Belly]

Guys, added the earth and all good...... for a short time
Played with the turbo timer: light came on consistantly with 22 second to go on a 1 minute timer setting??
N o issues if set to 30 sec. Go figure

[Chops]

Some say with the GU`s, and extra earth helps fix a variety of issues.

[mickldo]

I work on GU Patrol utes at work. We build most of the bodies for Ergon. On one of the ones we did we were spooling the winch cable on and we noticed the dash lights on the aftermarket switches that we fit were glowing while winching even though the circuits of the switches weren't on. Anyway, long story short, after a heap of diagnosis we found that the Patrols didn't have a good earth strap between the negative terminal of the battery and the chassis. There was one between the battery and the body but not the chassis. The winch was earthed through the chassis and there was small earth straps but obviously not enough for the full current of the winch under load. The winch was trying to find whatever earths it could through anything it could, including the dash wiring. Anyway, (I waffle on a bit don't I?) we fitted a dedicated earth strap for the winch and it fixed all of the problems. We had a couple of other problems and the earth strap fixed these too.

I am wondering if the lack of good chassis earth is the cause of these sub fuel tank problems. If the sub tank is attached to the chassis and the rest of the wiring is attached to the body and the earth for that circuit is getting a bit corroded it wouldn't take much for it to cause problems. Put on a decent sized earth between the battery and chassis and the problem should be solved. Especially if you have a winch fitted.

[Rapson]

I press the Sub Fuel button and get nothing, with a full tank. Not sure if it is the button or not but I should start there.

Any pointers on where to start looking for a fix? Have just bought the vehicle and have just started digging around for manuals etc and all are pretty vauge in this area.

Thanks in advance.

[YNOT]

The first thing I would be checking is the fuse. If the fuse is OK, leave it out for half an hour to reset the sub tank module.
After that, the most common cause of sub tank faults is a bad earth between the body and chassis. Most people fix this by adding another earth strap between body and chassis down the rear of the vehicle.

Tony

[Woof]

Have heard that if you disconnect the battery for a couple of hours it fixes the problem but only temporary, as Tony said that seems to be the main cause of it.

[macca]

Rapson, I have recently got a Patrol and have not figured out how the tank works.
With the sub full or with fuel in it and the main low push the switch in and a green light shows on mine.
Fuel is now transfering but its slow, takes maybe 1/2 to an hour to pump over.
Recently had the main empty and the sub full, got nervous and pushed the switch as it didnt seem to work automatically. Didnt want to run the main dry and have to prime the pump.
Still learning, and 175litres takes a long time to burn so I can fill up and have another go LOL
Macca

[YNOT]

Macca, your description of how the sub tank works is correct, and no, it's not automatic.

Tony

[dazmicho]

disconnect your battery completely for about 15 mins and then reconnect it. I recently had to do this myself, because i pulled a fuse out mometarily and that was enough to trip the sensor. Is there a light on your dash on as well that says subtank? If there is then your subtank button won't work until this is remedied. Of course you could take it to your local dealer and pay then a few hundred dollars to do what i just described.

[Hopetown Pub]

My sub tank pump works great until i use the turbo timer.
It trips out.
I turn battery power off. ( Cut out switch installed).
A few minutes later i turn battery power back.
Sub tank pump works. I have been told it is the way the turbo timer is wired into the thing the pump is wired to. Any suggestions. Cheers, Frank in the Flinders.

[YNOT]

Are you saying that if the sub tank pump is operating when you key off and switch to turbo timer that the pump cuts out? If you are then this is normal. Turbo timers are usually wired so all they do is keep the engine running, everything else goes off with the key. It can probably be wired differently but you would need to talk to an auto sparky about it.

Tony

[Hopetown Pub]

When iv'e been cruising around or on a trip and feel the need to use the turbo timer, i set it on 1,2,or5 minutes to cool down. I turn off the ignition & remove keys. Patrol idles away for the set time then shuts down. Upon restarting patto patrol the sub tank pump indicator light is showing on the dash and when i push sub tank start push in button,it does not work. I have to isolate then deisolate the battery to get it to reset itself. All is honky dori till i use the turbo timer again. This happens when useing the main tank or the sub tank. Your right about getting a sparky to rewire it Tony, hopefully it can be done. Thanks for helping mate, cheers.

Frank in the Flinders.

[Getabout]

I was reading thread in th hope of getting an answer to the sub tank problem but it seems to have left unresolved!
I to have the "sub tank" light on and yes the button does not work. it has been this way for 2years. I asked Nissan to fix it at my last (and I do mean last) service, they said " we do not know where the problem is"!
I have visited several forems regarding this issue and removed battery leads, added earth straps all with no fix.
has there been any new ideas come up lately?

[the godfather]

I assume you mean when the main tank isn't full? The sub tank button will only work once the main is down to around 3/4 full and it will also turn off before the main becomes completely full. So just to clarify, you are trying when the main is half empty aren't you?

[YNOT]

I was reading thread in th hope of getting an answer to the sub tank problem but it seems to have left unresolved!
I to have the "sub tank" light on and yes the button does not work. it has been this way for 2years. I asked Nissan to fix it at my last (and I do mean last) service, they said " we do not know where the problem is"!
I have visited several forems regarding this issue and removed battery leads, added earth straps all with no fix.
has there been any new ideas come up lately?

Silly question (a speciallity of mine) but has anyone checked to make sure the switch is properly pluged in?

Tony

[Mooka]

hi again, anyone know the tricks to the sub? my light is on on the dash but it wont transfer fuel. I can hear it transfering when i turn the ignition on and off for about 5 secs. it would be great if someone could help me out, i would like to go south soon, but very limited with one tank. Ive only had the car for about 3mths. I bought the 4500 litre. was it at vise choice? love the car though.

[Mooka]

Hi guys, i have the same trouble with my 2000 model GU. Had the problem when i bought it 3mths ago. Been asking around but no one knew what to do. Finally a mate put me onto this site, said it was a great place to meet people and you guys may be able to help me out. I 'll try to fix it on my days off. Thanks!!!!!!!!!!!!!!!!!!!!!!!!!!

[big datto]

could be the switch itself i swaped my mine for a simple on off switch and works a treat other one worked than stopped sounds similar to yours mate. but mine is gu ute diesel 4.2

[Pete's GU3]

F Y I ...re the sub tank , if you undo both fuel caps you can see the fuel being pumped into the main tank from the sub tank from near the opening .....interesting ...i thought it was pumped straight into the main through the guts ....anyhow this is one way to see if fuel is going in, if you dont have any warning light issues that is ....!!!!!!!

Anyway keep plugging away guys and try the suggested fix ups on this thread , i having failed, ended up taking it to nissan when i got it serviced and they just reset the computer changed a few fuses and all good now ...........

[Fitzy144]

Hey Mooka...... did you sort hte problem out?? My GU diesel had a similar problem from new, turned out the sender unit was installed in the wrong position and the float was hitting the side of the tank making the brain box think the tank was empty, so it wouldn't allow the pump to start.

Cheers

[Rellbell]

Sub tank lights Huh, I thought I was going mad. Our subtank light sometimes comes on when we are fully fuelled and going round corners. And when you use the spotties, the main fuel gauge drops fairly dramatically. But once you turn the car off and turn all back on minus the spotties, Fuel gauge reads correct. I have learnt to live with it, but will tell hubby about the previous post of cleaning the earth wire thou. We seem to think whoever wired in the spotties may have picked the wire for the fuel gauge and they take the power when we use spotties which is not often. cheers rellbell

[Rellbell]

hi again, anyone know the tricks to the sub? my light is on on the dash but it wont transfer fuel. I can hear it transfering when i turn the ignition on and off for about 5 secs. it would be great if someone could help me out, i would like to go south soon, but very limited with one tank. Ive only had the car for about 3mths. I bought the 4500 litre. was it at vise choice? love the car though.

Hey Mooka, The song goes "Love the one your with" It must have been the right car if you bought it. cheers Rellbell

[itchyvet]

The sub tank on my old 2.8 AND my new 3 liter works easily if you use 1/4 of your main tank, or even half, then turn on the sub tank and TRANSFER fuel to the main tank, when FULL, it will automatically turn it'self off.
I use the sub tank in this way until it's empty, usually around 280 to 300 K's per tank, then stay on the main.
Takes a bit of getting used to, but once used to it, no worries.
The manual also states that on turning on the engine, the sub tank tranfers fuel for a few seconds, (guess that's to check the system) for that reason, it pays to ALWAYS have fuel in the sub tank to prevent the pump from running dry.

[my third 256]

I press the Sub Fuel button and get nothing, with a full tank. Not sure if it is the button or not but I should start there.

Any pointers on where to start looking for a fix? Have just bought the vehicle and have just started digging around for manuals etc and all are pretty vauge in this area.

Thanks in advance.
main tank needs to be atleast a 1/4 empty for the sub tank to transfer fuel and light to come on

[Conradk]

I'm also having a run-around with the sub-light on and the transfer not functioning, despite all the clever tricks of disconnecting the battery. I'm at the point where I need to test the pump by hard wiring it into the battery but short of doing the wiring at the tank, where can I easily access the circuit to do this?

[Chappa]

mine has been running a muck to the sub tank is easy to hard wire if needed i just disconnected the sub tank control module behind the heater and ran a wire through a switch to the green and black wire that runs to the sub tank module and it will work fine just wont turn off automatically pretty sure its pin #1 by memory.

[Conradk]

Thanks Chappa. In the mean time I decided to have another bash but instead of disconnecting the battery for a few minutes I left it off for about 2 hours. Guess what, pure magic and the sub pump works perfectly. I can just hear the chorus saying "told you so; leave the power off until the system completely de-energizes". Having said that, were it not for this forum I would have never figured the promlem. Thanks guys.

[Sparkie]

Hi there! :gday:

Just for interests sake: The system will not work if a fault is detected anywhere...I had one the other day that did'nt
want to pump over to the main..removed the sender on the sub tank and found that the float had come apart due to
our corrugated roads in Namibia. It cost a bit of fiddling to reassemble and crimping on the flloat arm to get it working again...

Hope this might help somebody someday...(If I remember correctly,we cut a flap into the carpet for easy access....)

[Eben]

I am having issues with my sub tank and I believe the person who owned the car before me put in a long range tank. How would I go about finding the issue?

[MB]

I am having issues with my sub tank and I believe the person who owned the car before me put in a long range tank. How would I go about finding the issue?
G'day Eben, what issues are you having mate? Might pay to elaborate a little more for the crew here to help you out hopefully. Only issue I've ever experienced in a GU is dust impacted in the stock dashboard switch!

[alocke]

I had the same issue, after cleaning the mount point it worked again. Thank you for the posts.

[Cuppa]

I've found that if I overfill the main tank (ie. try to squeeze as much fuel in as possible) the sub tank light which shows each time the ignition is turned on & goes off after the the engine starts ..... doesn't do what it is supposed to to do, instead remains lit, making pumping from the sub tank impossible. I carry a jiggler hose just in case, but on the few occasions I've been through this drama disconnecting the battery after having used a bit of fuel from the main tank has rectified the issue.