Don't know if it will help, but I recall this being discussed a long time ago. As Craic mentioned, it had something to do with a sensor and forced the computer to go into "safe" mode. the speed limit is what brought it back for me.
But this is all from memory. Results will vary...
_________________________
'03SE
BFG AT/KO
Custom fuse panels for electrical mods
Custom backup solution mod (lights/camera/monitor)
Custom switched power outlets (8+ total)
Lots-o-Lights (6 driving lights, 10 total)
Original registration - Sep, '03
Pre-crash post count - ~1100