27,545m gas were used. then 19l 878m were used. if the gas tank hold 56l 22m how much gas remains?

It's the EVAP system. Code is for an open or short to ground in the gas tank vent valve. Pin hole in tank might cause a P0442 for a small EVAP leak, if the hole was large enough.

Much easier if the tank is empty. Siphon or pump the fuel out of the tank. Disconnect the negative battery cable. Raise the vehicle and install jack stands to ensure the vehicle is not going to drop on you. There are mechanical straps that hold the tank in place. There are also electrical connections for the fuel pump and fuel lines to be disconnected. Place a jack under the tank to support it and then remove the straps holding the tank in place. Lower the tank enough to gain access to the fuel lines and electrical connection. Disconnect the electrical and fuel lines and lower the tank until it clears the vehicle.
Be VERY careful with the fuel that was drained and whatever fuel remains in the tank. It is very dangerous.

One or two things. Does the cap lock with a key? If so, the cap is either still locked or is remaining in the locked position. Get it to a lock specialist as soon as possible. Another possibility is that the lip on the tank filler neck is damaged, and the solution is to force the cap off. If nothing else works, you can remove the filler neck from the tank by undoing the flexible hose that holds the neck to the tank, the bracket/s that holds the neck to the body of the car - this must be done usually from the underside of the car, and there should also be screws that hold the filler neck to the body inside the filler well. It is a finicky job, but if you can do this, you can take the neck complete with cap to someone who can help, or get a new neck from the dealer or a breaker yard and fit a new cap.

pull the tank and drain all the fluid out . Put in about 2 quarts of metholated spirits and swirl the tank around so that any remaining water is mixed with the spirits ( metho breaks down the surface tension of water and holds it in suspension--any metho left in the tank will pass through the system with no ill effects)

take the two remaining bolts and run all thread thru trunk

If there is rust inside, you need to buy a new tank. Best bet, go to the junkyard and get one. As far as getting it off, you need to take the bracket bars that hold it up. They go across the gas tank. Once they are off, if needed, locate remaining bolts on the edge of the tank. It will then come down.

Yes. It's not a terribly difficult job though. First back the car onto some ramps and set the parking brake firmly. Disconnect the electrical connector for the fuel pump / fuel level sending unit. You will need to loosen the hose clamps around the fuel filler neck hose and the vent hose and remove the rubber hoses at one (either) end. There will be some 'quick disconnect' fuel lines. To disconnect these, you need to squeeze the two white plastic inside pieces together and pull them apart (it will be very obvious when you see them). Put a hydraulic floor jack under the gas tank with a piece of wood on top of it to distribute the weight of the tank over a larger area. Then you can unscrew the two straps that hold the fuel tank up and gently and slowly lower it down. Once it is down, there is a lock ring on the top of the tank that holds the fuel pump / fuel level sending unit assembly in the tank. Use a brass punch to loosen the lock ring to avoid sparks. Make sure to replace the fuel strainer and any O rings when you do the pump. Installation is (as always) the reverse of removal. Also, remember to drain any remaining fuel from the tank while you have it removed. This will make installation a lot easier.

• You need to start by removing almost all the remain fuel, fuel is very heavy
• best method is to use a lift to get it off the ground, you could also use ramps to get the room need to drop the tank
• disconnect the filler spout from the side of the van
• disconnect the fuel lines
• use lifting equipment to support the weight of the tank, make sure this is stable
• carefully remove the tank straps and lower the tank, watch the fuel pump wiring and any other connection that may be in the way while lowering the tank.

yes, diesel is "dirty" compared to gas

The first thing you want to do is disconnect the battery to avoid any sparks..make sure you know your radio code before diconnecting the battery.second: Raise the rear of the car and secure it with jack stands,locate the connection point for the fuel line,just above the rear end assembly.Remove the two c-clip connecting the hose to the gas tank. disconnect the feed and return line allowing the remaining fuel to drain into a container. Once the fuel is drained, proceed to the trunk, remove spare tire and carpeting. disconnect the overflow seal from the filler neck,which will remain on the neck and come out with the tank . Disconnect the fuel sending unit located on top of tank. you should have two straps holding the tank in place, remove them and the tank will slide out.