2000 Land Rover Discovery II 111,452 miles

Battery drained. Lights on in weird places. Alarm going off. Took to Dealership for computer factory reset. Dealership saying BCU is defective. They said the front passenger door keeps opening and closing on their computer screen triggering the alarm. They said "we can wipe it out but it's just going to come back in a few minutes with the alarm on- you need a new BCU"

They want $2,000.00 with a 3 month wait.

What do I do?

 

 

Is the BCU defective from a drained battery? Are they doing something wrong ?

 

I would first suspect an issue with your front right door lock actuator/latch mechanism, I see it alot on mercedes, VW, and audi with bad latch actuators causing alarm issues. If the car is seeing intermittent open closed status, there is a good chance it is getting a bad signal from the door.

Find an independent rover or euro shop in your area and have them check it out.

A junkyard BCU can be installed assuming a shop near you has an autologic or equivalent high level scan tool to marry the BCU, ECU, and Gauge cluster so all are happy

 

Can a nanocom do the programming to link the ECU to BCU / cluster?

 

Um .. a drained battery can effect the door latch?

 

Um .. The other way around. The door latch can and will cause a battery drain if it is constantly cycling its open/closed signal to the BCU. Ever notice how the lights stay on for a little while after the door closes? The BCU reads door open/closed signals and lock/unlock signals to wake itself up for use.

IF you have a bad actuator/latch it can cause battery drains.

 

The lights were off. Car sat idle. Battery slowly drained. Then, the lights came on and the alarm sounded..

 

What is the solution....

Wait 3 months and pay the Dealer $2.000 or buy a used BCU off ebay and plug it in ?

 

You meed an ECU/BCU combo from the same truck. You can get both used for about $100. Make sure the you get SAI or non SAI depending on your truck. As others have said you may need an actuator for that door.