Not starting

[scimitarjohn]

We have a 53 reg 406 HDI, whether I lock the car or not on leaving it, after just over a minute the headlamps come on and then the alarm sounds (or at least tries to as there's a regular thumping noise from where the sounder is so I assume it's just not well) the alarm will reset each time the door is opened and shut and then repeat it's performance. One rather odd thing is that I can stop the alarm from activating by switching the radio on after removing the ignition key! Anyone any ideas, help or information, my local auto electricians best was to just deactivate the alarm system, but there must be some way of finding what the cause is.
A few months ago I had this problem that seemed to just go away after a short while, and no more problems until -
Car will not start, immobiliser ? only side lights, windows no go, heater no go, wipers no go, just about everything no go, turn key to start position and not turning over just a message 'power saving mode' on the graphics display. Once more does anyone have any ideas, help or information.

[steve_earwig]

When there's a lot of weird faults on a MUX 406 we usually send them here viewtopic.php?f=10&t=12118&p=107150&hilit=crazy#p107150

What's the charge like on the battery?

[scimitarjohn]

Many thanks for that, will check that out ASAP.

[GingerMagic]

Hi mate, when the car is in 'power saving mode' it just means it has shut itself down as the battery is being drained by the stereo, lights or something. This will not go until the car starts and it knows there is charge going back into the battery.
Have you tried to move the electric seats, they normally work even in 'power save'..

[dave406]

This can be an issue on GM cars were the alarm system internal battery is getting low it would sound the alarm

[mjb]

If there's an aftermarket stereo in there, remove it and see if the problem goes away. Otherwise do a search for the BSI reset procedure. Have you tried disconnecting the battery?

Was the car behaving perfectly before this started happening? Did all this just suddenly start one night?

[scimitarjohn]

Tried viewtopic.php?f=10&t=12118&p=107150&hilit=crazy#p107150 but connectors are in perfect condition, never had any water ingress in this car, all bone dry. The battery sits at about 12.7v, no electric seats to try but will put a clip on ammeter on the batt to check for abnormal drain. Where is the 'alarm internal battery' to check this? with my previous problem the alarm sounder did sound a very sick. Yes the car was fine when left in the evening but in this state in the morning. As I understand it a BSI reset means operating the drivers window, and the windows are no go.

[Puggy2]

Ref. BSI Reset here is link viewtopic.php?f=10&t=10968 Window down is so you can turn on ignition I had the same problem if you don't have internal alarm sensors on the "A" pillars then someone can sit in car. Hope this helps Iain