Alarm problems with Disco II
 

Bought disco II from repo auction and replaced damaged ignition with one from another vehicle that was being parted out. Vehicle comes to life electrically but will not start. Jumping starter relay allows vehicle to run for 1-2 seconds. Horn is honking and flashers flashing. Led on dash flashes but is not steady so I'm assuming it is not immobilized. I have seen many posts similar to this but could not find exact answer to my problem. I didn't get any paperwork with vehicle so no EKA code. Looking forward to getting it running and racing my favorite wife around our property in her LR3!!!

Reset the inerita switch on the fire wall and lock and unlock the doors 3 times in a row.

Inertia switch pushed but no click. I assume it did not reset. Tried door locks as you said but still no luck. The alarm appears to set (rapid blinking of led for about 10 sec) when doors are locked. When door unlocks led blinks quickly with about a 2 sec pause in between blinks. Flashers flash and horn sounds when drivers door is opened. Tried to start in neutral. No luck. Thanks in advance for your help. I've seen your replies in numerous posts--very good of you to offer your expertise.

Also, forgot to mention the key fobs do not lock/unlock doors. Does this have some effect??

I have been reading all the info I can on this issue and the alarm does seem to set when door is locked (rapid flash of led for 10 sec) but does not seem to disarm. Could really use some help. Tried the methods I have seen listed but the flashers start flashing as soon as drivers door is opened or if i sit in vehicle and lock and unlock with dash button the alarm starts as soon as key is put in ignition. I must be close--just need a response from someone who knows how to overcome this situation. Thanks

Unit may have sat without battery for so long that sync was lost between the ECU and BCU, requires a shop with proper computer to reset. Would be better if fobs were working, perhaps battery dead in them? BCU controls alarm and inhibits engine running, has to exchange coded data with ECU. You could also have a bad door lock switch that controls the alarm.

That makes lots of sense. I have another thought. I ended up purchasing the other disco 2 that was being parted out that I salvaged the ignition and key from. I put a battery in the car (the parts car) and the fob locks/unlocks doors, the engine turns over, fuel spits out (the heads and intake are all missing from this one) and everything seems to work as normal. Could I change the bcu from the parts car to the one I am trying to get running??? What are your thoughts on that??

If the led is on or flashing the car will not start. When the alarm is off the led goes off and stays off.

You can swap BCU but you'll need the ECM too. They are synced to each other (and your odometer, so it will flash... I suppose you could swap it too)

Also North American cars don't have unique EKA codes. They are all 1515

The alarm flashes rapidly for 10 sec when door locks. On and off when door unlocks. How hard is it to change ecu. Don't care about odo really. If the vehicle would run I would be fine with everything else. Just really going to use it on short trips into town and goofing off on our property/woods/creek. Where is ecu located and what does it look like??? Before doing that I will try the 1515 again. Of course the door key is now different that the ignition key because of ignition swap. Am i on the right track with changing bcu/ecu or should I try to fix the problem. Don't want to have to tow to the dealer that is almost 1 hour away and pay their prices. We just don't need the vehicle to be perfect--just running. My wife considers her LR3 "her perfect vehicle"!!

Also...replaced batteries in fobs..they light up correctly. Thanks for your help with this. It is greatly appreciated.

When I replaced my ECM and BCU, I had a specific code for a communications problem between the two computers. The symptoms of loosing the sync are that it will start and then immediately die.

Since your LED isn't turning off, you probably cannot even get it to crank with the key, let alone start. Sometimes the security system gets all angry if the battery gets low, and will not let you disarm. Let your battery fully charge, with all the doors closed (maybe the windows down, so you don't get locked out) and just walk away. Come back after half an hour or so after the batter is charged, and unlock the door with the door with the key. Hopefully the LED will turn off and you can start the car. If not, try the EKA.

I will try that first. Thanks for your help. I will post my progress. I just picked up a new battery and put it on a charger for the vehicle. I will install it this evening.

Tried eka with no luck. Tried a few different times waiting half hour in between. New battery with full charge in the vehicle. I may try bcu/ecm swap. Does the fact that they come from another unit that was working help me. Should they be synched together already??? I'm also going to see if there is a local shop that has computer to reprogram if necessary. Still open to suggestions.

Yeah. If they came from a running truck, you should be good to go.

Perhaps the drivers door lock actuator is bad. When you unlock the drivers door, do all the other doors unlock? You might have to unlock twice in a row, depending on how the BCU was programmed.

I still have not switched bcu/ecm but noticed that all doors unlock except door behind drivers door. It also does not lock/unlock from locking switch on dash. Can this cause alarm trouble. I still want to switch computers from other disco. Should have time in next few days.