2000 S80 strange problem

[rdc]

When I turn try to start my S80, the indicator lights on the instument panel stay on and the engine runs in the "limp" mode. Additionally, the shift position indicators on both the instrument panel and the console indicate the transmission to be in "park" regardless of where the shift lever is.I also get messages saying that there is either problems with the transmission or the brakes. Thinking that "rebooting" the computer may work, I disconnected and reconnected the battery. That worked! However, the problem has come back. Any advice will be greatly appreciated!