Below are description of the VT theft deterrent system and in addition, the HSV ESS system fitted to VT2 series HSV vehicles in Australia (I assume that NZ vehicles would be the same). From the descriptions in your original post, it appears as if the HSV component is working OK (only one beep and not five), but the VT component is having problems (I include the V6 and V6 supercharged engine descriptions for completeness, they are not relevant to your case).
VT THEFT DETERRENT SYSTEM
GENERAL INFORMATION
The theft deterrent system on VT Series Models uses a remote coded key to arm and disarm the system, as well as electrically lock or unlock all doors and tailgate (station wagon), or operate the boot unlock mechanism (sedan).
SYSTEM OPERATION
There are two modes of theft deterrent operation, armed and disarmed.
Armed
Once the theft deterrent system is enabled, it can be manually armed in one of two ways:
1. Actively, by pressing the lock button on the remote coded key or,
2. Passively, as the BCM will automatically arm 30 seconds after the ignition is turned off.
When the system is armed, the start relay (located in the engine compartment relay housing) and the powertrain management system (Powertrain Control Module (PCM) and on vehicles with GEN III V8 engines, Powertrain Interface Module (PIM)) are disabled, preventing the engine from being started.
Disarmed
With the system disarmed and the PCM/PIM enabled, the engine will be allowed to be started when the ignition switch is turned to the run position. The theft deterrent system can be disarmed in two ways:
1. Pressing the unlock button on the remote coded key. This unlocks the doors, turns the interior dome lamp on and disarms the system for 30 seconds.
2. By inserting the remote coded key into the ignition switch cylinder and turning the ignition to the ON or run position. This causes the BCM to read a security code serial data output from the remote coded key contact pin via the remote coded key reader assembly.
NOTE: Should the engine crank briefly when the ignition switch is turned to the START position (ie. due to misaligned or a faulty remote coded key reader) then pressing the unlock button on the remote coded key will also disarm the theft deterrent system.
Remote Coded Key
The theft deterrent system uses a remote coded key to arm and disarm the system, and electrically lock or unlock all doors and tailgate (station wagon), or operate the boot unlock mechanism (sedan models). The remote coded key is powered by its own internal battery. If its internal battery fails, the remote coded key can be powered by the remote coded key reader once the key is inserted into the ignition switch cylinder and turned to the IGN or START position.
When the theft deterrent system is armed by pressing the remote coded key lock button, the indicators will flash once and the theft deterrent alert indicator LED will begin to flash. Disarming the system by pressing the unlock button will cause the indicators to flash twice and the theft deterrent alert indicator LED will stop flashing. The Radio Frequency (RF) transmitted by the remote coded key is received by the BCM’s remote receiver located in the dash panel.
NOTE: Passive arming of the system does not automatically operate the door locks or flash the indicators.
The theft deterrent alert indicator LED is used to indicate the state of the system. A flashing LED indicates that the system is armed and consequently the vehicle cannot be started. When the LED is turned off, the BCM is disarmed and the engine can be started. The theft deterrent LED is incorporated into the trip computer switch assembly in the instrument panel facia.
V6 and V6 Supercharged Engine
When the ignition switch is turned to the ON position, the BCM polls the PCM and sends an encrypted BCM/Key security code (The security code is received via the BCM slip ring or remote receiver in the event of no slip ring communication). The PCM compares the received security code with it’s stored security code and if the codes match, the PCM will enable injector fuelling and continue engine cranking. The PCM will return an OK TO START message, which tells the BCM to jump from SHORT LOOP mode to the LONG LOOP mode.
GEN III V8 Engine
When the ignition switch is turned to the ON position, the BCM polls the PIM and sends an encrypted BCM/Key security code (The security code is received via the BCM slip ring or remote receiver in the event of no slip ring communication). The PIM compares the received security code with it’s stored security code and if the codes match, the PIM will continue enabling engine cranking and send a separate encrypted security code to the PCM. The PCM compares this code with its stored security code and if the codes match, the PCM will enable injector fuelling to continue. The PIM will return an OK TO START message, which tells the BCM to jump from SHORT
LOOP mode to the LONG LOOP mode.
NOTE: Regardless of the engine configuration, it is very important that the remote coded key reader is aligned correctly with the ignition lock assembly, or misalignment with the remote coded key contact may occur resulting in intermittent or no engine cranking or starting.
HSV EMBEDDED SECURITY SYSTEM
The HSV Embedded Security System (ESS) is a micro-processor controlled immobiliser which automatically interrupts four essential electrical circuits when in armed mode, preventing the vehicle from starting. The ESS stores important security codes and every time the vehicle is started it reads these codes. If any of these codes are different from the stored codes the ESS emits five beeps, enters armed mode, and prevents the vehicle from starting. If the ESS receives the correct codes it emits a single beep and allows the vehicle to start.
Operation of the ESS requires no extra input from the owner above the normal procedure of starting the vehicle. When ignition is switched off the module automatically enters armed mode. Disarming the system is achieved simply by inserting a correct key into the ignition barrel and turning it to the on position. Confirmation of the disarm is provided by a single beep. Conversely, if the vehicle enters armed mode when the ignition is turned on five beeps are emitted. The ESS has been designed so that in the event of power loss to the system (flat battery or theft attempt) it will return to the same operating state when power is restored. For example, if the system is operating in armed mode when the power is interrupted, it will return to the armed condition when power is restored.
To further enhance vehicular security the module is placed in a difficult to access location and is embedded into the vehicles main wiring harness. All wiring to the module is the same colour and of the same wire gauge.
A Security Information Card is supplied with the vehicle which contains the ESS PIN. This PIN is required by the authorised service agent in the event of either a Body Control Module (BCM) replacement or if new keys need to be programmed to the vehicle. The service agent contacts Australian Arrow Pty Ltd quoting this PIN. They then get the PIN converted to a particular security code which corresponds to a sequence of vehicular functions. By performing this sequence, which is different for every vehicle, the vehicle can be fitted with a new BCM or have new keys programmed to it. There are approximately 60,000 different codes available.
The HSV ESS is an electronic immobiliser which derives its main power feed from the car battery. However, the current consumption when the ignition is turned off is zero so there will be no adverse effects to your car battery.
