8G-4 IMMOBILIZER CONTROL SYSTEM
ON-BOARD DIAGNOSTIC SYSTEM
(SELF-DIAGNOSIS FUNCTION)
Immobilizer Control Module and ECM diagnose troubles which
may occur in the area including the following parts when the igni-
tion switch is ON.
ECM :
ECM/Immobilizer Control Module code
Serial data link circuit
ECM
Immobilizer Control Module :
Transponder code
Coil antenna
ECM/Immobilizer Control Module code
Serial data link circuit
Immobilizer Control Module
Ignition signal
With the ignition switch turned ON (but the engine at stop) regard-
less of the condition of the engine and emission control system,
ECM indicates whether a trouble has occurred in the immobilizer
control system or not by causing the immobilizer indicator lamp to
flash or turn ON.
Immobilizer indicator lamp is ON :
No trouble exists in the immobilizer control system.
Immobilizer indicator lamp is flashing :
ECM or Immobilizer Control Module has detected some trouble in
the immobilizer control system.
When ECM and Immobilizer Control Module detects a trouble, it
stores DTC corresponding to the exact trouble area in ECM and
Immobilizer Control Module memory.
DTCs stored in memory of each controller (Immobilizer Control
Module and ECM) can be read by using the procedure described
in “DIAGNOSTIC TROUBLE CODE CHECK (IMMOBILIZER
CONTROL MODULE)” and “DIAGNOSTIC TROUBLE CODE
CHECK(ECM)” in this section. NOTE:
As soon as the ignition switch is turned ON, ECM and
Immobilizer Control Module diagnose if a trouble has
occurred in the immobilizer control system. While the
diagnosis is being made, the immobilizer indicator lamp
stays ON and if the diagnosis result is “abnormal”, it
immediately changes to flashing but if the result is “nor-
mal”, it remains ON. Diagnosis takes about 3 seconds at
maximum.
