gubby

I have a MY05 WRX Wagon with a Sigma M30 alarm.

Increasingly the alarm goes off a little while after it has been armed.

It happens say up to 20 - 30 minutes after setting the alarm. As yet it has not gone off overnight thank goodness.

All I can think of is that if the seat belts have not fully retracted and one of them eventually moved, would that be enough to set it off?

Anybody else had similar problems as it is becoming a little embarrassing.

Sigma Sam

The M30 system has an adjustable Settle Time, following the system being armed during which the ultrasonics are inactive to allow for seatbelt and air movement within the vehicle, but this is usually set at 15 seconds (up to a maximum of 99 seconds).
If movement were to occur after this time, and the ultrasonic sensitivity is adjusted sufficiently high enough, then it is possible that seat belt movement 20-30 minutes later could trigger the system. However, I think it more likely that the sonics are adjusted to too sensitive a setting and that it is the changing air temperature within the vehicle that is creating air movement causing the system to trigger.

To confirm that it is infact the ultrasonics that are causing the alarm to trigger, and not another circuit, the LastTrigger Register can be recalled as follows (after keying the sequence count the number of flashes from the alarm's dashboard mounted LED):

- Arm then disarm the system.
- type: *17856*38#
- count LED flashes from alarm's dash mounted LED (not the keypad LED)

the flashes refer to the following circuits:
1= Ignition Circuit
2= Door Switch
4= Boot Switch
8= Bonnet Switch
16= Ultrasonic Sensors

If the trigger register does indeed confirm that the ultrasonics caused the last problematic trigger, then I would recommend that you reduce their sensitivity. Keying in the following sequence will set the sensitivity to the recommended setting for an Impreza:

- Arm then disarm the system.
- type: *17856*20*55#

When using the keypad always observe the following points:
- The digits should not be entered too quickly or too slowly - when a digit has been pressed the small LED built into the keypad will illuminate briefly as confirmation and only then should the next digit be entered.
- If an incorrect digit is pressed or the delay between entering digits exceeds10 seconds, then the LED above the keypad will flash rapidly and the PIN attempt should be abborted and started again after 30 seconds.
- Due to the small size of the keypad some users may find a rubber tipped pencil easier to use. DO NOT use the sharp tip of a ball point pen etc, or press excessively hard on the keypad as this will only damage the membrane and cause a digit to remain pressed, causing a continual incorrect PIN attempt leading to keypad lockout for 30 minutes.

If you should still encounter problems, or the last trigger register does not confirm the problem lies with the ultrasonic sensors then let me know as there are a number of other adjustments we can make.

Hope this helps.
SS

gubby

Cheers Sam. Thanks for the info.

Unfortunately er indoors triggered the alarm by setting it with one of the doors still open yesterday.

I shall wait for it to go off again and try to follow your advice.

sizzy1969

sigma alarm instructions being sold on ebay hope this helps