Car components : Immobilisers & Alarm

Rules

Applies to:

• Cars. A motor wagon that has a manufacturer's gross vehicle mass that does not exceed 4.5 tonnes.
• Buses.  An omnibus that has a tare that does not exceed 3 tonnes.

Does not apply to:

• Vehicles manufactured 25 years or more before the time of first application to transfer ownership.
• A vehicle classified as a farm vehicle.
• A vehicle exempted by the Director General.

Requirements

Three systems on a car can be immobilised:

• Fuel system - the fuel injection system or fuel pump is switched off.
• Ignition system - in this case the spark to the spark plugs is switched off.
• Starter system - the starter motor is prevented from turning.

There are 1, 2 and 3 stage immobilisers:

• Stage 1 means only one of the above circuits is immobilised.
• Stage 2 means two of the above circuits are immobilised.
• Stage 3 means all three circuits are immobilised.

The more circuits immobilised, the more difficult is it to steal the vehicle.

Choices

Choosing an immobiliser:

• Is it government approved and good installers are only fitting government approved immobilisers?
• What method do you like best for disarming it?

All immobilisers must have automatic arming.

• When the engine is switched off the immobiliser arms (turns off the circuits) after a specified time.
• All that is needed is a method of disarming the immobiliser.

There are a number of methods available:

• A hand held remote control.
• A jack plug.
• A touch key.
• A proximity sensor.
  

Alarms

A remote control or handset is used to disarm the immobiliser and operate some of the alarm's features. The remote control can be used to:

• Operate the central locking.
• Operate a panic feature.
• Operate a car finder feature.
• Open the boot.
• Arm or disarm the system. 

The LED warning light is the flashing red light you see on the dashboard of some vehicles. It acts as a warning that the system is armed and it can also indicate other features of the alarm.

On/off confirmation can be audible or visual. When the system is armed or disarmed either the indicators flash or there is an audible chirp from the alarm to indicate what the system is doing.

The car finder is a great feature that helps you find the car at night or when it is parked in a busy car park. When you press the button on the remote control either the indicator lights flash or the alarm makes an audible chirp.

When you hold down the panic button on the remote control the alarm sounds and the lights flash, warning off intruders or would be attackers.

Auto or passive arming - the alarm system automatically arms. If you are continually forgetting to arm the system this is a useful feature. Auto or passive arming immobilises the engine automatically and can only be disarmed by pressing the button on the remote control. This feature should not be connected to the vehicle's central locking system for obvious reasons - you may leave the keys in the vehicle and find, when you come back, that the doors have locked.

Retained memory - alarms can be programmed to perform certain tasks, like passive arming. If the power is disconnected from the system ie: the fuse is removed or the battery is disconnected, then the system can lose all or some programs. Retained memory automatically returns the system to its original status when the power is reconnected.

Automatic reset - if the vehicle is broken into and the alarm sounds it will continue for a specified period (usually 15 minutes). After this time the alarm will reset itself in readiness for any further attempted break-in.

Code hopping. This feature, which can also be called rolling code, jumping code, randomly encrypted code or non-grabbing code, is the latest technology in fighting car theft. The remote control emits a signal in code to the alarm control unit and this signal is changed each time the remote button is pressed. This feature was designed to defeat car thieves who use code grabbers or scanners to disarm alarm systems.

Multi-button remote control. The remote control has a number of buttons to operate extra features such as; panic warning, car finder or boot release.

Current sensing - the alarm is triggered by a change in voltage or current draw. This happens if a door is opened and the interior light comes on.

Pre-intrusion warning - this will warn the owner if the vehicle is being tampered with.

Shock sensing. The system contains a sensor to detect vibration caused by striking a blow to any area of the vehicle, including glass.

Ultrasonic sensors look like small microphones. They detect air turbulence caused by opening a window or door or an intrusion into the cabin space. Microwave sensor The microwave sensor acts like radar and sends out a signal, which can protect the vehicle's interior. This is especially useful in soft-top vehicles and panel vans. The sensor can be adjusted to be effective in pre-determined areas of the vehicle.