My wife's Disco II (2000) won't start and the alarm is acting odd. Clicking "unlock" on the key fob doesn't unlock the doors, but pressing "lock" does lock the doors. (Which leads me to presume it isn't a synchronization issue.) The door can be locked/unlocked using the key manually. However, trying to start the car causes the alarm to go off.

We get the identical behavior out of both of the keys and key fobs which leads me to think it isn't a fob battery problem. (Besides, clicking on the fob with the driver door open doesn't cause the alarm light to rapidly flash as the manual says it would to signal a low fob battery.)

I've seen reference in the forum to a low main battery causing the alarm to go off when trying to start the car (https://landroverforums.com/forum/sh...ighlight=alarm), but the car hasn't had any sluggish starts to suggest that the battery was getting low. It was cold last night (oh, down to about 3F or -16C) but by the time my wife tried starting it today the temps were just a few degrees below freezing.

Any suggestions on what I should try?

Thank you.

 

To close this out in case someone hits my question via a web search, today the car's battery was acting dead. Sure enough, when tested one of the cells was gone, so the odd way it was acting yesterday might have been due to a very low voltage situation. After replacing the battery the car starts like normal and the fobs are back to working for both locking and unlocking.