This is how Prado fuel tanks work

Matthew  Kelly has given a pretty good summary.

I’ve been using my 120 petrol for 20 yrs and found out from my mechanic and through experience the following.

Hope this helps.

1. Don’t think of the set up as a main tank and sub tank.
That’s an old school set up where you’d switch over from one tank to the other where the Prado is a little different.

2. The Prado has two 90L(approx)  tanks.

3. The 1st  tank supplies the fuel to the engine.
The 2nd tank supplies fuel to the 1st tank that then supplies it to the engine. It’s like the 2nd tank tops up the first all the time until it’s empty.

Sooo

When the fuel gauge has no green light on, the needle is indicating the % of the TOTAL fuel capacity of the Prado (approx 180L) eg 2/3 showing is 2/3 of 180L.

When the needle gets down to 1/2 way on the gauge you are down to 1/2 total capacity (180L/2 = 90L)

Now….. if you stare at the gauge intently for the next few km’s as you drive (not recommend!) you’ll see the needle flick back up to the full position and the green 90L light comes on at the same time.

This is now indicating you have the 90L primary tank full (the second tank is now empty)

The needle is now indicating the % of your remaining 90L tank and will then fall like a normal car fuel gauge as the primary 90L tank is used up.

(It’s a good way of giving you a more accurate reading on that last 90L).

You’ll also notice as a result it drops a lot faster as it’s indicating % of 90L rather than % of 180L.

Also note that if you stop the car shortly after the green light has come on, and leave it sit for a while,  the next time you start the car the green light may be off and the needle pointing at 1/2 way again. It’s just reverted to telling you you have 1/2 of 180L (90L) as it did just before it switched to green light (90L) and full indicating.

I suspect it’s done this as when you stopped the vehicle, there’s been a little bit of fuel pumped from the secondary tank into the 1st one triggering your Prado to think it’s got just a tiny bit more than 90L and therefore turning off the green light.

Now finally with the green 90L light on, the gauge will drop down like a normal car gauge until it gets almost to empty when the ORANGE low fuel warning light comes on.

My Prado then has approx 50 to 80kms  left to travel before it’ll run dry. This will depend on the fuel consumption at the time.

I say approx because I’ve never run my tanks dry as it’s not a smart thing to do. In fact I try to never go below 1/4 so I’m not sucking up any crud off the bottom of the fuel tank.

So the picture you show indicates you’re basically running on fumes and better find a gas station quick!