I've got a 99 Grand Cherokee and the fuel gauge fluctuates from full to empty (regardless of how much fuel is actually in the tank). The Trouble Code is P0462: Fuel Level Sending Unit Volts Too Low. I've replaced the in-tank fuel sending unit (along with the fuel pump), but this has not fixed the problem. I'm contemplating replacing the in-dash fuel gauge next even though it still shows movement when doing the dash test (hold down odometer reset button then turn key on).

Has anyone had this same issue? Can anyone offer a solution?

Thanks,
Caleb :o)

I would suspect a bad connection since empty is 0 volts.

I would suspect a bad connection since empty is 0 volts.

Thanks Bob... I thought that too until I noticed that the fuel gauge sometimes stays at full even when the tank is close to empty. It fluctuates back and forth between empty and full regardless of how much or how little gas is in the tank.

Any other ideas?

Sounds like a bad meter. Did you do an open and ground test from the sender end of the wiring? Open is empty and grounded is full. Do the test from the dash area if it doesn't respond from the back end.

Sender spec: 20 ohms..float up, 270 ohms..float down..as per FSM.

as per FSM.

What is FSM ? Foolish Service Manual ?

as per FSM.

What is FSM ? Foolish Service Manual ?
Factory Service Manual. It's your friend.