Immobilizer System - Mitsubishi LANCER EVOLUTION 2003 Technical Information Manual

54A-4
The engine immobilizer system prevents the engine
from starting and immobilizes the vehicle if a key
other than the key registered for that vehicle is used
in an attempt to start the engine after forced entry.
The engine immobilizer system consists of the igni-
tion key, key ring antenna, immobilizer ECU, and
engine control module (ECM). It works in the follow-
ing way and has these functions:
1. After the ignition is switched on, the engine con-
trol module sends a control signal and transpon-
der read command signal to the immobilizer
ECU.
2. When the immobilizer ECU receives the control
signal from the engine control module through
the key ring antenna, the immobilizer ECU sup-
plies a current and sends random number data to
the transponder in the ignition key.
3. The transponder uses the random number data
to derive an ID code, which is sent to the immobi-
lizer ECU through the key ring antenna.
CONSTRUCTION DIAGRAM
TRANS-
PONDER
CHASSIS ELECTRICAL

IMMOBILIZER SYSTEM

POWER
(WIRELESS)
ENCRYPTED
CODE (WIRELESS)
IMMOBILIZER SYSTEM
4. The immobilizer ECU compares the ID code that
was sent with pre-registered ID codes, and if it
matches, a control signal approving ignition is
sent to the engine control module. If the ID code
does not match (in the case of counterfeit ignition
keys, for example), the immobilizer ECU sends a
control signal denying ignition to the engine con-
trol module, preventing the engine from starting.
5. The system is designed to be maintenance-free
because the power source for the transponder is
supplied by the immobilizer ECU. Two ignition
keys are provided, and up to four keys can be
registered to one vehicle (one receiver) as
needed. There are one million possible combina-
tions for the registered ID codes. In addition, one
part of the code is changed each time the key is
switched on, which improves security by prevent-
ing theft using a copied ID code.
NOTE: If the immobilizer ECU is replaced or if the
ignition key is lost or additional keys are requested,
the MUT-II or III must be used to reset all transmitter
ID codes. During the resetting process, all transmit-
ters must be re-registered because the registered ID
codes will be erased.
IMMOBILIZER
KEY RING
ECU
ANTENNA
M2540003000069
CONTROL
SIGNAL
ENGINE
CONTROL
MODULE
MUT-II/III
AC210964 AB