IMMOBILIZER SYSTEM
CHASSIS ELECTRICAL54A-5
IMMOBILIZER SYSTEM
M2540003000490
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,
engine-ECU and engine-CVT-ECU . It
works in the following way and has these functions.
1. With the ignition key turned ON, the transponder
(a small transmitter) integrated in the ignition key
transmits its own encrypted code to the ring
antenna via radio wave.
2. According to the sent encrypted code, the immo-
bilizer-ECU controls the engine-ECU or
engine-CVT-ECU only when the sent
encrypted code agrees with the pre-registered
one.
3. The system is designed to be maintenance-free because the power source for the transponder is
supplied by the immobi lizer-ECU. Three ignition
keys are provided, and up to eight keys can be
registered to one vehicle as needed. More than
one trillion of encrypted code combinations can
be registered, and parts of them are irregularly
changed whenever the ignition key is turned ON.
This feature prevents code copying, resulting in
higher security of the system.
DIAGNOSIS CODE TABLE
Diagnosis code No.Diagnosis item
11Transponder communication system or r adio interference of encrypted code
12Encrypted codes are not the same or are not registered
CONSTRUCTION DIAGRAM
AC306415AD
M.U.T.-III
Ignition
key ring
antenna
Immobilizer-
ECU
Ignition key
Encrypted
code
Transponder Power
(Wireless)
Encrypted code
(Wireless) Control
signal
Engine-ECU
or
engine-CVT-
ECU
MAIN CO MP O N E N TS
Component name Outline of function
Immobilizer-ECU with an
antenna•Supplies electrical power to the transponder integrated in the ignition key,
and transmits random number data.
•Verifies the encrypted code which is sent from the transponder. If the code
is correct, it sends an engine mobili zation signal to the engine-ECU
or engine-CVT-ECU .
TransponderIs power-supplied by the immobilizer-ECU. When the transponder receives
random number data, it processes it an d the encrypted code. Then it transmits
the process result to the immobilizer-ECU.
Engine-ECU or
engine-CVT-ECU Starts the engine, and then continues the engine running if an engine
mobilization signal is co nfirmed. If an engine immobilization signal is
confirmed, the ECU cancels the engine control and stops the engine.
