January 16, 2008

Vehicle immobilizers

By Jim Kerr

Recently, I received a letter from a Manitoba driver who is having problems with his truck after an Immobilizer system was installed. Immobilizers are electronic devices that prevent a vehicle from starting and are designed to reduce vehicle thefts. Manitoba is unique in requiring Immobilizer systems to be installed on high theft risk vehicles before they can be registered in that province. Even if a vehicle isn’t on their high risk list, they still recommend the installation of an aftermarket Immobilizer for about $140.00, but do offer a $40 dollar annual reduction in vehicle insurance premiums for vehicles equipped with Immobilizers.

This situation might sound like it wouldn’t affect you unless you are in Manitoba, but Immobilizer systems, both factory installed and aftermarket systems, can be found in vehicles across Canada. Transport Canada Standard CMVSS114, which became law on September 1, 2007, requires all new vehicles to be equipped with an Immobilizer system. This doesn’t apply to older vehicles already in the country but does apply to imported vehicles built after September 1, 2007, and if those vehicles don’t have a factory Immobilizer, an aftermarket one must be installed.

While Transport Canada does not endorse any particular system, only a few aftermarket systems meet the Transport Canada standard. The Insurance Bureau of Canada and Underwriter’s Laboratories of Canada (ULC) developed the Canadian Standard for Automobile Theft Deterrent Equipment and Systems: Electronic Immobilization; (Can/ULC-S.338), which formed the basis for the Transport Canada Standard and currently they have approved systems by Masterguard, Autowatch and PowerLock.

As you might expect, there is limited information available about the detailed installation and electronics of these Immobilizer systems, probably to deter thieves. This type of information is usually only provided to accredited installer facilities. General information on the systems states that a transmitter on the key or key fob sends a radio signal to a module in the vehicle when the key is turned. This module then powers up vehicle operating circuits. Some systems are connected directly to the starter circuit, while others connect into several circuits, including starter, ignition and fuel injection circuits. Unless the module that is installed in the vehicle receives the correct code, it will not allow the vehicle to start.

Some systems use a fixed code – one that remains the same every time, but most systems, including all the factory Immobilizer systems I have studied, use a revolving code. With literally millions of code combinations, the correct revolving code changes every time you start the vehicle. The module and transmitter are synchronized to the same code progression and can be reset to start the progression over again if necessary to re-synch the system. Revolving codes are virtually impossible to “break” so a thief can’t sit in the parking lot with a receiver and “learn” your vehicle code. The code you just used no longer works the next time!

Immobilizers are excellent at preventing vehicle thefts, assuming you don’t leave the keys in the vehicle, but I am not a big fan of installing aftermarket systems such as these on vehicles. In the past four to five years, the electronic communication systems have become extremely complex, with many modules on the vehicles. Even the factory engineers sometimes have problems with integrating modules into the vehicles and they have far more testing capability than the aftermarket manufacturers. I understand the desire to reduce vehicle thefts, but installing systems that may or may not have been tested on your particular vehicle seems to be a troublesome and costly way of doing it for vehicle owners. Even the Insurance Bureau of Canada states that “Generally, vehicle manufacturers reserve the right to deny warranty in instances where it can be proven that the vehicle fault is directly attributable to the installation of any type of after-market equipment, not only IBC-approved theft deterrent systems.” To diagnose a problem, the manufacturer’s dealership may have to temporarily disconnect the system and restore the vehicle to the way it came from the factory. This is done at the vehicle owner’s cost even if the vehicle problem is covered under warranty!

The gentleman from Manitoba was required to have an Immobilizer installed on his 1993 pickup truck. About seven to 10 days later, the battery was dead, completely frozen and the case split open. After installing a new battery, the vehicle was checked for any electrical drains with only a normal 10 milliamps drain found and everything OK. Seven days later, another battery was dead again and frozen. While this problem could be caused by a light staying on, such as an underhood light, the only change to this vehicle, that had been trouble-free in the past, was the addition of an Immobilizer. The problem could be a poor installation, or the Immobilizer module itself, but regardless of the cause, the aftermarket Immobilizer needs to be disconnected to diagnose this vehicle – likely at the owner’s cost. That’s why I don’t like many automotive aftermarket electronics devices.

Jim Kerr is a master automotive mechanic and teaches automotive technology. He has been writing automotive articles for fifteen years for newspapers and magazines in Canada and the United States, and is a member of the Automotive Journalist’s Association of Canada (AJAC).

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