Suzuki GRAND VITARA Owner's Manual page 1688

10C-16 Immobilizer Control System:
Troubleshooting
Step
1 Diagnostic Trouble Code (DTC) confirmation
1) Clear DTC(s) referring to "Diagnostic Trouble Code
(DTC) Clearance: ".
2) Turn the ignition switch to OFF position.
3) Check if any DTC is detected referring to "Diagnostic
Trouble Code (DTC) Check: ".
Is DTC P1621 still detected?
2 Fuse check
1) Check if any related fuse is blown.
Is any fuse blown?
3 Immobilizer control module (ICM) poor connection
check
1) Disconnect immobilizer control module (ICM) connector
"G24" referring to "Immobilizer Control Module (ICM)
Removal and Installation: ".
2) Check if wire connections are normal at immobilizer
control module (ICM) connector "G24".
Is each wire connection normal?
4 ECM poor connection check
1) Disconnect ECM connector "E23" referring to "Engine
Control Module (ECM) Removal and Installation: in
Section 1C".
2) Check if wire connections at "E23-13" and "E23-28" wire
terminals are normal.
Is each wire connection normal?
5 Check for open in power supply wire circuit
1) Connect immobilizer control module (ICM) connector
"G24" referring to "Immobilizer Control Module (ICM)
Removal and Installation: ".
2) With the ignition switch at ON position, check voltage
between "G24-1" wire terminal at immobilizer control
module (ICM) and body ground.
Is voltage about 12 V?
6 Check for open in ground wire circuit
1) With the ignition switch at ON position, check voltage
between "G24-2" wire terminal at immobilizer control
module (ICM) and body ground.
Is voltage 0?
7 Check for open in communication wire circuit
1) Disconnect immobilizer control module (ICM) connector
"G24" referring to "Immobilizer Control Module (ICM)
Removal and Installation: ".
2) Disconnect ECM connector "E23" referring to "Engine
Control Module (ECM) Removal and Installation: in
Section 1C".
3) Check resistance between "G24-3" wire terminal at
immobilizer control module (ICM) connector and "E23-
28" wire terminal at ECM connector.
Is resistance infinite?
Action Yes
Go to Step 2.
Replace blown fuse(s)
with new one(s).
Go to Step 4.
Go to Step 5.
Go to Step 6.
Go to Step 7.
Repair open in
communication wire
circuit.
No
The troubleshooting is
completed.
Go to Step 3.
Repair poor
connection(s).
Repair poor
connection(s).
Repair open in power
supply wire circuit.
Repair open in ground
wire circuit.
Go to Step 8.