We were told that our engine (transmission) control module is bad. Will that make it difficult to add gas or make it overlow after only adding about 2 gallons?
Look around in the owner’s manual and under the gas filler cover and you likely will find a notice that you should not top off the tank and re-fueling. Are you or any other drivers in the habit of topping it off?
Even if no one is topping it off, it still be be the same problem. The vapor recovery system can cause this problem. You may need a mechanic for that one.
Also it may be a safety device designed to keep fuel from leaking if the car is not right side up after an accident. In this case you may be able to see a ball blocking the hose in your car to the fuel tank. If so you may be able to dislodge it and have it fall back towards the tank.
I can’t imagine any possible connection between the two problems.
Get a mechanic to diagnose it. I would guess that the problem is in your evaporative emissions system. This captures gasoline vapors in the tank and sends them to the combustion chamber to be burned. If this isn’t working correctly, these vapors will remain in the tank and not be displaced when you add fuel. The pump will shutoff, thinking the tank is full.
If your state’s gas pumps don’t have the rubber boot over the nozzle, try barely inserting the pump nozzle in the tank so as to leave an air gap to allow the vapors to escape.