i have a sigma m series alarm on my car,
This is from straight from the book, and i wont take blame if it messes up your car!
READ IT ALL BEFORE TRYING IT OUT!!!!
"with the ignition switched
off and the security system
disarmed type into the keypad the following
* * A A A A
* 9 2
* B B B B
* B B B B
#
Where
AAAA represents the old 4 digit pin code and
BBBB represents the newly chosen 4 digit pin code. You have 10 seconds to enter each character. If you do not press the characters in time the LED on the keypad will flash rapidly, after which you must start again from the beginning. To confirm correct input of your PIN code the siren will bleep after entering the last digit. The number 92 is the access code/command which notifies the security system unit to accept new pin code.
So for example if the existing PIN code is 1234 and you wish to change it to 6789 you would type in:
* * 1 2 3 4 (Old pin code) (The alarm will bleep)
* 9 2 (Notifies the alarm to accept the new pin code)
* 6 7 8 9 (Enter new pin code)
* 6 7 8 9 (Confirms new pin code)
# (Stores the new pin code to the alarm. This will be followed by a bleep)
Hope it helps