Land Rover Repair: service lights, obd ii scan tool, battery cables

Question
The service engine is on in my 99 Discovery II, there are 97,000 miles, however when resetting by disonnecting the battery cables this works for a few weeks, I'm assuming this is a reminder light.
However my biggest concern is the ABS,TC,and picture of the vehicle going down hill light remains on. What should I check for and does this need to go on a diagnostic as this stuff gets real expensive with Landrover
Thanks

Answer
Why do people assume warning lights don't mean anything?

Your service engine light is on because there's a problem.  Find a shop with an OBD II scan tool and see what the stored codes are and see where that leads.

Disconnecting the battery will just cause other problems down the road for service personnel.

You will need a shop with the specialized Land Rover test system to rear the ABS codes.