'00 Discovery, 261K, ACE equipped, everything works, everything's great. Sitting in bumper to bumper traffic and after a few starts/stops, the ACE warning light flashes red and a chime sounds every few seconds. It will continue to do so until I shut off the engine, and restart. The chime and red light cease, unless I'm still in stop/go traffic, then it will reoccur a few moments later.
Just changed the fluids, pump is fine, no leaks, fluid topped off. Not sure what to look for. The only time this occurs is stop and go traffic backups.

Any suggestions would be appreciated.

Thanks to everyone!