Alarm Probs

November 17, 2005

I got a 2001 MR2 Roadster and this morning I clicked my keypad to open the doors and the alarm went off - even though I could start the car and drive it off etc. I couldn't turn the damn thing off for 15 minutes and apart from waking everyone up in my block (nice!) I had to suffer the indignity of driving to work with the alarm wailing the whole journey!!

<_<

Obviously the alarm and immobiliser aren't connected but I was wondering, does anyone else have problems with the factory alarm going off on, say, cold mornings? Might it have something to do with the weather? And how can I turn it off?!

Sorry if I sound like a loon but I bought this 2nd hand from a friend who'd lost the owner manual and I'm loathed to take it to a dealer for a checkup... prapps an alarm specialist would be cheaper?

Any info/advice would be much appreciated!

:)

November 17, 2005

Well here's what I've found out... apparantly the Battery loses about 1.5 volts for every degree the outside temperature drops below freezing.

The Battery when fully charged shoud be 12v, and although the car will start as low as about 9v, the alarm needs 11v to operate properly. Last night was about -3 so I'm guessing it lost close around 4 volts, hence the alarm malfunctioned.

Can anyone confirm or deny the logic to this? Either way, it looks like I'm either gonna hafta:

a. get a new Battery

b. get a new alarm

c. have it rewired at a garage or alarm specialist

d. all of the above

November 20, 2005

e. Disable it

Who takes notice of alarms these days?(unless your driving with it going off :D

Sorry for the useless reply:)

November 20, 2005

Well here's what I've found out... apparantly the battery loses about 1.5 volts for every degree the outside temperature drops below freezing.
The battery when fully charged shoud be 12v, and although the car will start as low as about 9v, the alarm needs 11v to operate properly. Last night was about -3 so I'm guessing it lost close around 4 volts, hence the alarm malfunctioned.
Can anyone confirm or deny the logic to this? Either way, it looks like I'm either gonna hafta:
a. get a new battery
b. get a new alarm
c. have it rewired at a garage or alarm specialist
d. all of the above
←

Not convinced by the 1.5 volts per degree below freezing claim. By that logic, if it were just a few degrees below zero nobody's car would start. I'm pretty sure that cars with standard batteries will start without problems at many degrees below zero.

My Gen 7 Celica never had a problem with the alarm going off in cold weather. It did malfunction if I left coins near the sensor; if you do a search you'll find other people have had simlar problems with various newish Toyotas.

November 21, 2005

Yeah disabling it has to be the short term answer. Maybe even the long term one too. I took it to an alarm guy on Saturday and he told me the brain had gone in the alarm, it's a Sigma something or other. So regardless of the cold weather, sounds like it was ****** anyway.