System Description

WARNING: This page is about a different car, the 2008 Acura TL and 2007 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.

The vehicle is equipped with a type IV immobilizer system that will disable the vehicle unless a programmed ignition key is used.

This system consists of a transponder located in the ignition key, an immobilizer control unit-receiver, an indicator, imoes unit (Except '07 USA models), and the ECM/PCM.

When the immobilizer key is inserted into the ignition switch and turned to the ON (II) position, the immobilizer control unit-receiver sends power to the transponder in the ignition key. The transponder then sends a coded signal back to the immobilizer control unit-receiver which sends a coded signal to the imoes unit, which confirms the code and signals the ECM/PCM to supply power to the fuel pump circuit.

A communication agreement with the HDS is required at the ECM/PCM or the imoes unit after repair or replacement. When replacing the immobilizer control unit-receiver, all keys are required to be registered into the new control unit-receiver. Any keys that were not registered in the control unit-receiver will not start the vehicle.

Fig 1: Immobilizer Control Unit-Receiver - Communication Diagram

Courtesy of AMERICAN HONDA MOTOR CO., INC.

If the programmed key has been used, the immobilizer indicator will come on for about 2 seconds, then go off. When the ignition switch is turned OFF, the indicator will blink for about 5 seconds to signal that the unit has reset correctly, then the indicator will go off.
If the wrong key has been used or the code was not received or recognized by the unit, the indicator will come on for about 2 seconds, then it will blink until the ignition switch is turned OFF.
IMMOBILIZER INDICATOR BLINKING PATTERN:

Fig 2: Immobilizer Indicator Blinking Pattern Chart
Courtesy of AMERICAN HONDA MOTOR CO., INC.