AUTOELECTRICS MOBILE PRODUCT SERVICES
Telford Shropshire UK 01952 247007

Vehicle Security

Car auto electrics & mechanical  breakdown callout to Telford , Shrewsbury,& Shropshire areas.                                                                www.autoelectrics.net 

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

A car is often one of the most valued possessions owned. Vehicle  door 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. Skillled Auto locksmiths can also usually remove broken keys from ignition  lock barrels.

Car alarm systems are fitted to discourage unauthorised tampering or theft from a vehicle. The bad guy will probably use a brute force method involving vehicle damage to gain unauthorised access.
Alarms provide an audible siren and possibly visual warning when activated.
Many manufacturers now incorporate key coded security systems and a factory fitted alarm as standard.

Types of protection - Car alarm features and functions 

If the vehicle is raised, eg by a tow truck ,or by somebody jacking the car up to remove wheels, a tilt sensor will activate the alarm

Passive arming

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

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.

Vehicle Electronic Control Unit (ECU) Immobilisation

This type of immobiliser is integrated into vehicle electronic system computer control units during manufacture.

A coded signal is required before certain functions will operate.

There are three common types of this system .

 Remote Control Key Fob

The first 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 or infrared signal to a receiver unit mounted inside the vehicle which then passes a data code to the engine 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.

Transponder Keys

The second 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.

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 www.thatcham.org

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.

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.

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;

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 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