Do CAN-BUS alarms require skill to install?
Aftermarket CAN-BUS alarms in theory are much easier to install compared to none CAN-BUS alarm. On a very basic level is just a case of connecting the alarm to the vehicle data wires, supplying the alarm with a good power supply and hooking up light outputs and the horn or siren.
Often the manufacturer provides a cheat sheet showing which colour wires to connect to. On the face of it this reduces the level of skill and knowledge needed, but it’s not always that simple.
The difference between a good CAN-BUS alarm with quality firmware installed well and a budget system with junk firmware is huge.
In one of my previous posts I explained what a CAN-BUS alarm is and the advantages they have over a PLIP alarm system.
One of the most important aspects of an alarm is how it arms and disarms. Here I explain that it is not always simple and why the installer needs to know what they are doing.
Arming and disarming
Vehicle specific data
The data the alarm reads to arm and disarm varies massively between vehicle brands.
The alarm needs to arm and disarm with the factory keyless entry system, be that a remote or a proximity smart key.
Different vehicle platforms
What data the alarm uses depends on what signals are available on the specific vehicle.
For example, my Honda Vezel alarm arms and disarms when it receives a remote signal. The alarm will arm or disarm regardless of a door being open or closed.
In contrast, most Toyota alarms will not arm if a door is open, so the alarm looks for both the remote signal and the doors locking.
Installer knowledge - Skills and experience
As an installer it’s good to know what is happening with the system and understand the quirks of how the alarm works with specific vehicles.
Part of my job is to make sure that the alarm can not be cheated into a non-remote disarm. This is just as important for a CAN-BUS alarm as it is with a PLIP alarm.
The CAN-BUS systems in some vehicles do not carry the remote locking signals. For example, the H200 Toyota Hiace (2014-2020) has CAN-BUS data for the doors being opened or closed, but no data for the central locking, let alone remote locking.
Nissan CAN-BUS alarms
Most Nissan models produced from around 2005 to 2015 share the same CAN-BUS platform. There is no signal available for remote locking so most CAN-BUS alarms get around this by monitoring the central locking in conjunction with hazard lights flashing.
The remote lock/unlock commands generated by the BUS network can be replicated simply by pressing the hazard switch and manually locking/unlocking the vehicle and cheating the alarm into disarming.
Compromised alarms
Clearly this is not an acceptable solution, yet I’ve lost count of how many alarms I’ve been able to cheat with this method.
I know that this is an issue with the following Nissans:
- D40 Navara
- NV350
- NV200
- Y12 Wingroad
- Tiida
It’s not only Nissan where CAN-BUS alarms can have compromised arm/disarm signals. It also affects the Mazda Demio and the Mazda 3.
CAN-BUS alarm disarm inhibit methods
Which CAN-BUS alarms prevent this diisarm cheat?
Vodafone Automotive CAN-BUS alarms fix this issue with an additional inhibit wire. This tells the alarm not to disarm if there is any activity on the hazard switch.
This works in a similar way to most OEM/PLIP upgrade alarms. The installer still needs to take care that the alarm is correctly installed.
A thorough check should always be done to make sure that there is no easy way to defeat the alarm.
Knowledge and skill make for a better alarm installation
A good alarm installation is all about selecting the right system and having a skilled technician. This is just as important for a CAN-BUS alarm installation as it is for an old school remote alarm.
