Vehicle Security


Vehicle Alarms , Immobilisers , Security Door Locks for Vans, DVR 12v / 24v CCTV Camera Systems , Battery Isolator Switches

A vehicle is often one of the most valued assets owned. The vehicle may also be carrying items of value which could be a target for theft.  Increasing vehicle security involves raising the level of difficulty to deter the potential criminal.

Vehicle Security Dead Locks

Dead locks are a first line of defence against unauthorised entry.

If you have lost your car keys a good auto locksmith will easily open mechanical vehicle door or ignition locks without original keys or vehicle damage ,and may be able to cut new car keys without the original keys present. Security deadlocks may only be cut by specialist locksmiths. Skilled Auto locksmiths can also usually remove broken keys from ignition  lock barrels.

The bad guy will probably use a brute force method involving vehicle damage to gain unauthorised access.

Vans may be fitted with additional security door locks to improve cargo security and lockable steel tool storage bolted or welded inside the vehicle to provide extra defence if door locks are compromised

Staff training should be provided to ensure vehicles arer parked up in well lit areas with additional security such as CCTV or security guard

Car alarm systems

Quality Car alarm fitment can discourage unauthorised tampering or theft from a vehicle. Alarms provide an audible siren and possibly visual warning when activated.

Canbus alrm systems are easier to fit than the older hard wired types of alarm because there is less cables to install but only really applicable to vehicle models manufactured after 2013


Many manufacturers now incorporate key coded security systems and a factory fitted alarm as standard.

Types of protection - Vehicle alarm features and functions

Perimetric protection or perimeter activation,

This means the alarm control unit is wired into pin switches on doors, bonnet, boot, fuel flap, etc. Often the same switches used for the courtesy light , so the alarm will sense when a door is opened. car alarm pin switch

A glass breakage detector may be fitted.

Volumetric security

Vehicle alarms may also offer interior protection or volumetric security. Volumetric protection uses ultrasonic or microwave detectors which can detect changes to the air volume within the vehicle cabin as a person moves.

Tilt switches

An tilt switch or inclination sensor will activate the alarm if the vehicle is raised, eg by a tow truck ,or by somebody jacking the car up to remove wheels.

Panic function

A push button may be fitted allowing the alarm siren to be activated by pressing the button in an emergency. The panic button may also activate emergency vehicle tracking devices on certain equipment.

Passive arming

The alarm system may be switched on automatically when the occupants leave the car , this is referred to as Passive arming.

Immobiliser function

A vehicle immobiliser is designed to prevent unauthorised starting and driving of a vehicle. The Immobilizer may be wired to the vehicle alarm system so that the alarm siren & lights flash if activated.

Vehicle immobilizers exist in a variety of types:

Electrical Circuit Isolation

This type of immobiliser is designed to physically interrupt various vehicle circuits which will prevent the vehicle engine from starting. Aftermarket alarm and immobiliser units often offer this type of protection.

Coded Vehicle Electronic Control Unit

(ECU) Immobilisation type of "factory fitted" immobiliser is integrated into vehicle electronic system computer control units during manufacture disabling ignition or fuel injection functions of engine management computer to prevent vehicle operation. A coded signal is required before certain functions will operate. Electronic access to control units is required to bypass this system often via vehicle on board diagnostics port. To prevent OBD port connection a range of protective guards is available. Faults occuring with this type of system may require computerised diagnostics.

 Touch key Immobiliser

Autowatch 239Ti touch key Immobiliser


  • Automatic arming
  • Two circuit Immobilisation
  • PIN code over ride
  • Illuminated touch key receptacle status indicator
  • Anti tamper Security housing
  • The touch key system is self arming when the vehicle ignition is switched off. The active immobiliser function isolates various circuits to prevent the vehicle from being started by unauthorised persons. To deactivate the vehicle immobiliser a special touch key is placed against a dash mounted receptacle.

    Remote Control Immobiliser
    This type uses a remote control fob transmitter (often known as a 'plip') which requires the user to press a button to send a coded radio frequency rf  signal to a receiver unit mounted inside the vehicle which then passes a data code to the control computer. On receiving the correct code the computer allows the engine to be started when the ignition key is used.

    If an incorrect code is received certain functions are disabled preventing startup.

    Vehicle Tracking Devices

    Vehicle trackers can be installed, these are often subscription based services requiring GSM access to provide real time vehicle location.

    Autowatch 172 Ri Remote Immobiliser


  • Encrypted remote Control
  • Self arming
  • Immobilisation to prevent unauthorised vehicle startup
  • PIN code over ride
  • Central locking output
  • Illuminated touch key receptacle status indicator
  • Anti tamper Security housing
  • Indicator / Light flashing
  • System upgrades available to full alarm with battery backup siren

  • Transponder Vehicle Keys
    This type is a coded key system where the ignition key contains a coded device or microchip which is read as the key is inserted into the ignition barrel (the ignition barrel is surrounded by a pick up coil)

    If the correct coded key is used an encrypted  data signal is sent to the relevant vehicle control unit to authorise full function.

    If an incorrect key is used ,either with the wrong code or without a code chip , the vehicle control unit will disable various functions to prevent unauthorised start up.

    New keys may be added to the system or keys replaced or deleted but may require a security code to allow programming of keys.

    Vehicle key programming was once a main dealer only job but there is now equipment available with key programming functions available to independent vehicle repairers and locksmiths.

    In some instances the vehicle manufacturer may provide an alternative method to bypass  the vehicle immobiliser for emergency starting if transponder keys or remotes have been lost . EKA Emergency Key Access details will often be advised within the vehicle operators manual.

    Key Code Access pad
    A further variation of the coded immobiliser system uses a keypad which requires the driver to enter a secret code by pressing the keypad buttons. The key code access system is particularly useful in cases where vehicle keys are stolen because the vehicle still needs entry of a pin code to deactivate the immobiliser system.

    Thatcham Security Rating

    The Motor Industry Repair Research Centre at Thatcham,Berkshire,UK, carries out testing of both new vehicle security features and provides a rating system for vehicle alarms and immobilisers.

    Link to Thatcham vehicle security page at

    Insurance Approved Alarm / Immobiliser System
    Usually this term applies to immobiliser systems which meet one of the thatcham category specifications and have a thatcham approval number. Some insurance companies will provide discount on the insurance cost if your vehicle is fitted with an alarm or immobiliser.

    Alarm arming activation
    The alarm may be armed or activated by means of a door lock switch, or a remote control device.
    Remote controls used infrared (IR) or radio frequency
    signals. The remote control sends a coded signal to the alarm control unit to activate. Rolling code or random encrypted code technology may be used to prevent this code being picked up by a scanning device . The rolling code will change each time the alarm is activated or deactivated.

    A problem can occur if either the remote control fob or vehicle battery fails causing the code synchronisation between remote transmitter and control unit receiver to be lost. This may require a defined procedure to resynchronise devices.

    Battery back up
    The alarm unit may have an additional internal battery fitted to provide power to the alarm system should the vehicle starter battery be disconnected.

    Central door locking function
    Central door locking systems allow all vehicle doors to be locked from one point.
    Vehicle locks are moved from the lock to unlock position and vice versa by motors or solenoids fitted within each door.
    Aftermarket central door lock (CDL) motors are either two wire or five wire types. The 2 wire type operates on a power supply & ground to lock and connection reversed to unlock.
    The 5 wire central door lock actuator also contains switches to activate / deactivate the system.
    A typical 4 door power lock system would use 5 wire actuators on the front doors , and 2 wire actuators on the rear doors.
    A further development of central door locking is deadlocking or double locking.
    Double locking uses the CDL motors to disconnect the door lock linkage from the lock preventing an intruder from opening the vehicle door by smashing a window and pulling the lock button from inside the vehicle.
    Shielding plates may also be fitted to further increase security & prevent access to lock linkages & motors.

    Some car alarm systems may be wired into a central door lock module to enable remote locking.

    Full closure alarm system
    A total closure alarm system may be connected to both central door locking and electric windows / sunroof. The full closure function may close all windows and door locks when activated.

    Car stereo anti-theft system

    The car alarm may also be connected to the vehicle in car entertainment system. If the entertainment system is disconnected the vehicle alarm may be activated and also immobilise.

    The car stereo may also require a code to be entered after power supply disconnection (battery removal) and reconnection before it will operate.

    If a car radio code has been lost it may be possible to obtain the code from the supplying dealer or have the radio decoded.

    Remote Paging, Vehicle tracking and Text alert.

    Autowatch KS999
  • Stand alone tracking system
  • Can be installed as combined pager and tracking system
    linked to an alarm system
  • Real time vehicle location shown on website map
  • Click here for more information opens in new browser window
  • Vehicles may be located and position tracked using a GPS device ( similar to a mobile phone signal ) .

    Top of the range car alarm systems may provide a text alert to a designated mobile phone if the vehicle alarm is activated. Some SMS messaging alarm systems allow the owner to send an activation code from a designated mobile telephone to disable or enable the vehicle alarm system.

    Vehicle tracking systems can also offer benefits to fleet and service companies by providing logistics data and remote asset monitoring.

    Some systems offer real time vehicle position location over the internet allowing service companies to reduce labour and fuel costs.

    Removal of alarm and vehicle immobilisation due to breakdown

    If the alarm or immobiliser is to be removed or bypassed this should be agreed with your vehicle insurance company beforehand as it may affect your policy.

    Diagnosis & Troubleshooting

    My car won't start , the immobiliser is faulty , the alarm siren goes off without warning.

    A few reasons why an immobiliser may fail:

    Remote plip batteries can become discharged.

    Spurious radio interference may affect some immobiliser devices causing failure to decode.

    Control units may develop faults often due to water ingress ,vibration, or component age.

    Failure of wiring looms

    Vehicle battery or memory back up discharges causing loss of control unit memory , often known as control unit amnesia because the coding between remote and receiver loses synchronization. This can happen to vehicles fitted with a body control module ( BSI module ) if the recommended battery removal procedure is not followed.

    Because your vehicle refuses to start does not necessarily mean that you have an immobiliser fault.

    Vehicles can fail to start for numerous reasons including;

  • Battery failure
  • Fuel shortage : Fuel system component failure eg, fuel  pump etc
  • Fuel quality : contaminatd or incorrect fuel
  • Discharged starter battery due to faulty charging system, wiring problem  
  • Engine management or fuel injection or ignition component failure
  • Mechanical faults

    Computer diagnostics of manufacturers integrated factory alarm systems


    Vehicle alarm & central door lock systems can be complex with a variety of switches,modules and sensors.
    Diagnosing the cause of breakdown can be assisted with computerised equipment .    A scan tool diagnostic test may reveal stored fault codes which can prevent engine starting, eg 'key code not recognised','ecu function blocked by immobiliser','fuel system pressure sensor fault',etc.
    Function tests of door locks and switches etc may be completed using computerised equipment .

    Mechanical Anti theft devices

    Primary and Secondary immobilisation can be performed by the use of mechanical devices which prevent operation of vehicle controls or movement of the vehicle.

    Examples are :

  • Steering lock
  • Gearshift lock

    Steering wheel covers, lock bars, brake and clutch pedal locking bars,handbrake locks,wheel clamps, fuel system shut off devices, driveway bollards etc.

    Commercial Vehicle Cargo Protection

    Additional methods to protect vehicle cargo and personnel include  

  • High security van door locks & deadlocks
  • Lock shielding
  • Van Safes
  • Cargo area alarm systems
  • CCTV monitoring with DVR Digital video recording
  • Vehicle tracking solutions
  • Starter battery isolation switches
  • Key out  Run stop system installation to allow vehicle engine to run with ignition key removed
  • HGV Air braking system lock to prevent unauthorised driving
  • HGV Semi trailer fifth wheel lock
  • Wheel Clamps