Land Rover Repair: Discovery II service engine light, range rover p38, rovacom

Question
hi, i have two question my service engine ligth is on and, this never happen  before, can you tell the reason for this?, and i have another problem when i am driving a have a noise at the passanger side, like a bottle of water is moving, can your tell what happens and how to reapir this problem , thanks

Answer
On Early Range Rover p38's and (I believe) the DII, the "service engine" is a timed reminder that comes on every 50,000 miles, to remind you to do a tune-up.  This can be reset and/or turned off by any shop with a proper LR diagnostic tool.  (Autologic, Rovacom, Testbook).

I don't know what the water sound is, possibly the gas tank sloshing?