Hi there! I am a newbie to the Land Rover world, I am a Jeep convert... I bought a 2000 Discovery II a couple of months ago, and so far I am very happy! Just a few things I would like to discuss, as I didn't do my homework before my buy( I know naught me!).
Here is a list of my problems concerns:
1. Three amigos. Mine are there, always... As soon as I turn my engine on they are there until I turn it off. I am sure I need a brake job, including rotors... Will that fix this?
2. Check engine light... It is always on and peridiodically flashes at me while driving.
3. SRS light... That came on since I have owned it.
4. A little red truck light with arrows pointing to the side of the the truck. Usually comes on during a turn. It beeps a lot then the light stays on.
5. A wobble during hard braking.
6. A nasty squeal during engine acceleration. It doesnt squeal while the engine is at idle.
7. A small ticking in the engine. Not sure how to describe this... It is not very loud, but its there.
8. Air suspension. It was converted to spring suspension, do I want to keep it this way or possibly convert it back?

A little about what I have learned from the forums. I use only premium gas. The three amigos have something to do with either the hubs or abs module. I should really do the 60K service ASAP. And that Disco's are awesome

 

1. need to pull codes(special scan tool)..could be as simple as brake dust could be as costly as needing a new shuttle vavle in the ABS(save up money for the last one)
2. pull codes..any autoparts store
3. pull codes..probably requires a special scan tool not sure
4. no idea..ACE light maybe?
5. have brake rotors turned
6. may be just the belt..use belt dressing to see if that helps
7. could be a lifter...seaform in engine..change oil
8. thats up to you..air rides better but air bags leak about 50-80k miles

 

What he said plus...
If the air ride was not turned off a warning light will come on when you load the truck or make hard turns because the SLS (self leveling suspension) keeps the truck level at all times, no SLS no level thus warning light.

Replace the serpentine belt, if squeal continues replace the belt tensioners.

SRS (supplemental restraint system) warning light, common on DII's. Buckle and unbuckle the passenger seatbelt a dozen or so times, if the passenger belt does not get used much the sensors inside the buckle get dirty and set off a fault code.
Another common problem is the wire harness at the floor that connect to the seatbelt come loose or get corroded, unplug them, clean with electrical contact cleaner and plug back in.

Wobble during hard braking, warped rotor or bad hub, if it is a bad hub that will set off the 3 amigo's.

Check engine light flashing means you are damaging the engine and DO NOT drive.

Add Marvel Mystery Oil to the crank case, drive for 500 miles or so and then change the oil and use a diesel oil.
The tick should go away, sticky valves are common if the wrong grade of gas was used.