Alarm issues with Diesel saloon

[DieselHonda]

Hi All,

2008 Diesel Saloon ( 2003 to 2008). In the last few months the alarm would go off in the car. What was interesting was the indicators were not flashing, and anything I did, remote locking and key locking, starting and driving the car made no difference, alarm still going off. It happen a few times when I was out, car was at home. I think after about 15 minutes it would stop. I did try disconnecting the car battery and once I would connect it up again , off it would go again.  Any ideas?

 

Other info,

 Car seemed slow to start for a while, then one day not enough power to start, fitted new battery Ok now ( Mid Nov 2022) For about six months the remote opening from the key ( same for both keys with new batteries) I have to have the key nearly touching the door glass for it to work. Yesterday the car failed to start and was slow this morning and this evening when going to work ( one hour journey) . Checked voltage with engine off once home and it is 12. 3 volts. 

[Trevor]

First thought is that it may be a poor earth connection which could be causing the slow starting issue (even if the battery has 12.3 volts) as the power will not be reaching the components that require the earth return (e.g. starter motor)
As for the alarm, could be worth checking all earth connections and leads to ensure tight and free from corrosion.
After that I would check all the sensors (bonnet, boot, doors, etc) to see if the interior light goes off when opened and closed

Finally check for any water ingress into the electrics, underbonnet relay and fusebox and also underneath the dashboard