Vauxhall Factory fitted Alarm and Immobiliser (Thatcham Category 2)

The button on the drivers side ultrasonic sensor housing is a "pet" button.
Pressing this button just before you exit the car and set the alarm will disable the ultrasonic sensors in the car's interior.
This allows you to lock and alarm the car while leaving a dog in there.

Fault codes can be read out of the Alarm by shorting pins A and H
(NOTE: ## on later models (?) this no longer works ????)

 

The code is flashed out on the ultrasonic led in the roof lining, passenger side

The Ultrasonic "pet" button clears the codes.

 

18	Fault with disarm signal
32	Boot   caused an alarm condition
33	Bonnet caused an alarm condition
34	Doors  caused an alarm condition
35	Ignition Turned on caused an alarm condition
36	Immobilization circuit open circuit
37	Radio caused an alarm condition
38	Ultrasonic caused an alarm condition
39	Fault with disarm signal. (central locking fuse blown)
46	Rear Window smashed caused an alarm condition  ('92+ models only)
52	Horn Voltage Low ‑ Horn O/C or fuse blown

The immobiliser control unit has links to the anti theft alarm system. The immobiliser will not disarm if the anti theft alarm is active or has been triggered.