Whining, hard to accelerate, check engine light

Forget the fuel pump. The engine is running, so the fuel pump has to be working.

You need to list the engine size so we can look up the correct information for your van. The transmission has gone into "limp" mode because the Transmission Computer detected a problem and shut the system down. Limp mode keeps the transmission in second gear to allow you to drive slowly to a repair shop without needing a tow truck.

There are going to be diagnostic fault codes stored in the Transmission Computer. It is important now to not disconnect the battery or let it run dead until those codes have been read and recorded. They will provide valuable information to your mechanic. You can get a general idea of the severity of the problem by observing when it goes to limp mode. Turning the ignition switch off, then restarting the engine gets it out of limp mode. Then, if you shift to "drive", then it starts out right away in second gear and stays there, it is most likely sensor or electrical-related. If it starts out in first gear, like normal, and up-shifts to second, and maybe third, then suddenly bangs back to second gear, it is more likely the cause is excessive slippage in one of the clutch packs. That will set fault codes related to "gear ratio errors".

Regardless of what is causing it to go to limp mode, if you force the van to run at highway speed, the engine will be running much too fast and will eventually cause damage to it.

Please scan the computer for codes to see if you have a transmission code which will confirm the transmission is having problems.

Here is a guide to help you.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run this test and get back to us so we can continue helping you.

Best, Ken