Eclipse L4-2.4L SOHC (2004)
Ignition Switch: Description and Operation
IGNITION SWITCH
GENERAL DESCRIPTION
IGNITION KEY REMINDER TONE ALARM
The ignition key reminder tone alarm will sound under the following condition, and warn the driver to remove the ignition key.
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The driver's door is opened when the ignition switch is at "LOCK" (OFF) or "ACC" position without removing the ignition key.
However, the light reminder tone alarm will take precedence over this function.
IMMOBILIZER SYSTEM
The immobilizer system consists of the ignition key, the key ring antenna, the immobilizer-ECU, and the ECM <M/T> or PCM <A/T>. 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 a registered ignition key is lost, all your ignition keys need to be
registered again using scan tool MB991502 (MUT-III) to ensure security (refer to How To Register Encrypted Code). An additional ignition key can be
registered as follows (only if no ignition keys are lost):
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Using scan tool MB991502 (MUT-III) (Refer to How To Register Encrypted Code.)
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Registering new ignition keys by operating ignition keys that already have been registered (Refer to How To Register Encrypted Code.)
CONSTRUCTION DIAGRAM
1. When the ignition switch is turned to "ON" position, the ECM <M/T> or PCM <A/T> sends a requirement for the encrypted code to the
immobilizer-ECU (at this time, the engine is remobilized).
2. When the immobilizer-ECU receives the requirement from the ECM <M/T> or PCM <A/T>, the immobilizer-ECU supplies power to the
transponder inside the ignition key via the antenna. The energized transponder sends the encrypted code back to the immobilizer-ECU via the
antenna.
3. The immobilizer-ECU judges the encrypted code with its code logic in itself. If they are identical, the immobilizer-ECU sends the encrypted code
to the ECM <M/T> or PCM <A/T>.
4. If the ECM < M/T> or PCM < A/T> can not receive the encrypted code, the engine will be immobilized.
DISPOSITION WHEN REPLACING IMMOBILIZER SYSTEM RELATED PARTS
