Fuel level in the trip computer.

I don't know exactly where I read this on this board, weither it was in this part or one of the other places that have the same van like this.

The person was talking about something about the trip computer saying he had only used like 20 gallons of gas and the tank was empty, yet he had the ext model van which has the 25 gallon tank in it. My 2003 I just picked up seems to do this.

I got thinking if this is all controled by the body computer and there is only a few models of this BCM4 for the vans with the bells and whistles and the BCM3 for the ones without the bells and whistles and they use them on the regular vans and the ext models maybe they are all programmed to know only a 20 gallon tank?

On my 2000 montana all i ever use is trip fuel use gauge since my real fuel gauge is broken. I think it has nothing to do with the size of the tank becouse if you dont reset it it will keep adding on the gallons way above 25. Since i dont want to run out of gas i always assume it reads two gallons less then what has been used. In reality its probably off by a littel more then a gallon. I think it measures how much fuel by the injectors.