How to change the original Accord car anti-theft feature

In 2003 Accord is one of the most successful models of Honda, regardless of its appearance or technology at the time the same level models have a great advantage of this model is now also seen as a classic, which makes the car created at the time of sale of legend. But the car also has a problem that often the door had been broken into, items inside the car theft phenomenon. The reason the car can easily be stolen, but also from its anti-theft system.

2003 Honda Accord uses a third-generation anti-theft system. This antitheft system implemented by an engine in addition, the remote control when the car lock after 15 s, the door also into the security state. First, let us look at the car’s security alarm system
When the doors, bonnet and luggage compartment closed and locked, security alarm system will be put to work. Before the system work, the ignition switch must be in the OFF position, the key must be removed and the integration control device multiplexer MICU must receive a door, the tailgate and the engine cover are closed and locked signal.

If a key cylinder switch improperly adjusted, is not normally locked, or there is a short circuit, the security alarm system will not work, the vehicle can not enter the security state. If the security alarm system to work, the engine cover is opened, and the door or the trunk lid unlocking improperly, will receive the ground signal MICU corresponding switch, the reference voltage 10 V is reduced to 0 V, then the alarm security alarm system; If the audio HVAC display device is disconnected, the loss of an input terminal to ground, the voltage input to ground will rise to 10 V, security alarm system will alarm (alarm sound). Be more specific, after the vehicle into the security state, the following actions will lead to a security alarm system alarm.

① skid doors or tailgate is open.

② use of a key or the remote control is not open the door.

③ engine cover is opened.

④ audio HVAC display device is disconnected. When

alarm security alarm system, the horn will sound, while the external light shining 2min, the driver’s door with a key or press the UNLOCK button on the remote control can be terminated at any time alarm.


By the above described security alarm system and a circuit diagram of a control (FIG. 1) easy to see, when the vehicle enters alarm state , if the thief smashed the glass, open the door from the inside of the door or stolen audio equipment, security alarm system will immediately alarm. However, if a method screwdriver Alice’s door lock cylinder to open the door, security alarm system does not work. This is what causes it? Here we need to look at the car door alarm system.

The circuit diagram can be seen, after four doors, the tailgate and engine cover all closed, disconnect the ignition key, the remote control LOCK key is pressed after 15 s, the vehicle into the security state. Further, without using the remote control while the use of mechanical key lock door into the security state can also, because there is a key cylinder lock switch at the driver’s side door, this door lock switch is that criminals have multiplicative the machine. Because this switch not only having a door lock and the security state of the vehicle entry function, but also has a door unlocking and releasing theft effect. That is, when the vehicle into the security state, using a mechanical key lock / unlock the door locks, anti-theft system is not cause alarm, which led to the theft of illegally open the door alarm will not trigger the alarm system.


Accord in 2006 made a improvements to solve the problem of the door without warning when pry, so exactly how solve it? Simply put, it is to improve the design of the driver’s door key cylinder switch. 2006 Accord car door key cylinder switch in addition to a previous model of the wire, i.e. the white wire between the No. 1 terminal of the driver-side door key cylinder switch connector to the end of the door UNLOCK multiplexing control unit (FIG. 2), so that, when the vehicle enters alarm state, even if the owner is also triggered by a mechanical key to unlock the anti-theft alarm system, the same core picking illegal theft security system can also cause alarm. I got the inspiration from improved this feature, if the door key cylinder switch 2003 Accord’s this white wires do not pick, canNo 2006 Accord and get the same anti-theft functions? This is confirmed by experiments feasible.

Methods How to change the original Accord car anti-theft function described in this article is that simple, but this simple approach has significantly strengthened the car’s anti-theft feature. One thing to note is that after doing this function changes, users can only use a master key to open the door with remote control, because the key 2003 Accord with only a remote control, so if people use vehicles, we need more several matches keys with remote control. Today, many models are already available door burglar alarm function, while most similar to the Accord’s functionality, so the methods described herein can be extended to other models, but also hope you are interested in the maintenance industry colleagues to practice.


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