Antitheft and Alarm Systems: Description and Operation

IMMOBILIZER SYSTEM
The immobilizer system consists of the ignition key, the key ring antenna, the immobilizer-ECU, and the ECM or PCM . The ignition key has a built-in transponder. The key ring antenna is installed on the steering lock key cylinder. Only the registered ignition key permits the engine to start, therefore, the engine can never be started by means of a forged key or by connecting the ignition wiring directly. The system is significantly safe and reliable against theft. In addition, the driver has only to turn the ignition switch to the "ON" position to activate the immobilizer system. If the requirements for starting the engine are not satisfied, the engine will be immobilized. If the ignition key is lost or another ignition key is added, the encrypted code can be registered or erased by using scan tool MB991502 (MUT-II)

THEFT-ALARM SYSTEM
When the theft-alarm system has been armed if a door or trunk lid is opened, the horn will sound and headlight flash (high-beam) intermittently for a period of 180 seconds.

This system is controlled by the ETACS-ECU and front-ECU.

The system is composed of the components described below.

PANIC ALARM
With the theft alarm function armed, pressing the panic button on the keyless entry system transmitter causes the theft alarm horn to sound for about 180 seconds in an attempt to prevent theft. The alarm is turned off by pressing any switch on the transmitter.

TONE ALARM FUNCTION

Ignition Key Reminder Tone Alarm Function
When the driver's door is opened (driver's door switch ON) without removing the ignition key [ignition switch to "LOCK" (OFF) or "ACC" position], the tone alarm will sound intermittently to remind the driver that the ignition key has not been removed.

Light Reminder Tone Alarm Function
When the driver's door is opened (driver's door switch ON) with lighting switch (taillight switch or headlight switch) in the ON position and ignition switch in the "LOCK" (OFF) or "ACC" position, the tone alarm will sound continuously to remind the driver that the lights (taillights or headlights) are ON. This function does not work if the taillights or headlights are switched 0ff through the headlight automatic shutdown function. In addition, the ignition key reminder tone alarm function has a priority over this function.

Door Ajar Tone Alarm Function
If any of the doors are open, with ignition switch "ON" and with vehicle running at the speed of 8 km/h (5 mph) or more, ETACS-ECU makes buzzer sound.

Low Washer Fluid Level Tone Alarm
If 10 seconds have passed after ignition switch has been turned "ON," and then, washer fluid level switch remains at the position "ON" (alarms for washer fluid level getting low) for two seconds or more, ETACS- ECU makes buzzer sound.Buzzer sounds just once after setting ignition switch to the position "ON."

Seat Belt Tone Alarm Function
When the ignition switch is turned to "ON" position without fastening the seat belts (seat belt switch OFF), the tone alarm will sound for approximately six seconds to warn the driver to fasten the seat belts. When the seat belts are fastened, the tone alarm will stop sounding.

Low Fuel Level Tone Alarm Function
If seven seconds have passed after ignition switch has been set to the position "ON," and then, low fuel level signal (low fuel level alarm light) from ECM or PCM, is turned "ON," ETACS-ECU makes buzzer sound.Buzzer sounds just once after setting ignition switch to the position "ON."

THEFT-ALARM SYSTEM

Theft-alarm System Operation
If a door or hood is opened, when the theft-alarm system has been armed the horn (theft-alarm horn) will sound and headlights flash (high-beam) intermittently for a period of 180 seconds.

Panic Alarm Function
With the theft-alarm function armed, pressing the panic button on the keyless entry system transmitter causes the horn (theft-alarm horn and horn) to sound for about 180 seconds in an attempt to prevent theft. The alarm is turned off by pressing any switch on the transmitter.