Suzuki Grand Vitara JB627. Manual — part 426

10C-16 Immobilizer Control System:

DTC P1621: Immobilizer Communication Line Error

S6JB0BA304012

Wiring Diagram
Refer to “Immobilizer Control System Wiring Circuit Diagram”

Detecting Condition and Trouble Area

Check for short to power supply wire circuit in CAN
communication wire circuits
1) Measure resistance at the following wire terminals with

the ignition switch at ON position.
Vehicle equipped without ESP

® system

• Between “E03-6” wire terminal at ABS control

module connector and body ground

• Between “E03-12” wire terminal at ABS control

module connector and body ground

Vehicle equipped with ESP

® system

• Between “E53-13” wire terminal at ESP

® control

module connector and body ground

• Between “E53-44” wire terminal at ESP

® control

module connector and body ground

Is voltage 0 V?

Go to Step 8.

Repair short to power
supply wire circuit in
CAN communication
wire circuits.

Check of keyless start control module power and
ground wire circuits
1) Check keyless start control module power and ground

wire circuits referring to “Keyless Start Control Module
Power and Ground Circuit Check in Section 10E”.

Are they in normal?

Replace keyless start
control module with a
known-good one and
recheck.

Repair malfunctional
wire circuit.

Step

Action

Yes

Detecting Condition

Trouble Area

Communication error between immobilizer control module
(ICM) and ECM is detected by ECM.

• Related fuse(s) blown
• Poor connection at immobilizer control module (ICM)

connector

• Poor connection at ECM connector
• Open in power supply wire circuit
• Open in ground wire circuit
• Open in communication wire circuits
• Short to ground wire circuit in communication wire

circuits

• Short to power supply wire circuit in communication

wire circuits

• Short of communication wire circuits
• Immobilizer control module (ICM) faulty
• ECM faulty

Immobilizer Control System: 10C-17

Troubleshooting

Step

Action

Yes

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?

Go to Step 2.

The troubleshooting is
completed.

Fuse check
1) Check if any related fuse is blown.

Is any fuse blown?

Replace blown fuse(s)
with new one(s).

Go to Step 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?

Go to Step 4.

Repair poor
connection(s).

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?

Go to Step 5.

Repair poor
connection(s).

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?

Go to Step 6.

Repair open in power
supply wire circuit.

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?

Go to Step 7.

Repair open in ground
wire circuit.

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?

Repair open in
communication wire
circuit.

Go to Step 8.

10C-18 Immobilizer Control System:

Check for short to ground circuit in communication wire
circuit
1) With immobilizer control module (ICM) connector “G24”

and ECM connector “E23” disconnected, check
resistance between “G24-3” wire terminal at immobilizer
control module (ICM) connector and body ground.

Is resistance infinite?

Go to Step 9.

Repair short to ground
wire circuit in
communication wire
circuit.

Check for short to power circuit in communication wire
circuit
1) With immobilizer control module (ICM) connector “G24”

and ECM connector “E23” disconnected, turn the ignition
switch to ON position.

2) Check voltage between “G24-3” wire terminal at

immobilizer control module (ICM) connector and body
ground.

Is voltage 0 V?

Go to Step 10.

Repair short to power
supply wire circuit in
communication wire
circuit.

10 Check for open in communication wire circuit

1) With immobilizer control module (ICM) connector “G24”

and ECM connector “E23” disconnected, check
resistance between “G24-4” wire terminal at immobilizer
control module (ICM) connector and “E23-13” wire
terminal at ECM connector.

Is resistance infinite?

Repair open in
communication wire
circuit.

Go to Step 11.

11 Check for short to ground wire circuit in communication

wire circuit
1) With immobilizer control module (ICM) connector “G24”

and ECM connector “E23” disconnected, check
resistance between “G24-4” wire terminal at immobilizer
control module (ICM) connector and body ground.

Is resistance infinite?

Go to Step 12.

Repair short to ground
wire circuit in
communication wire
circuit.

12 Check for short to power circuit in communication wire

circuit
1) With immobilizer control module (ICM) connector “G24”

and ECM connector “E23” disconnected, turn the ignition
switch to ON position.

2) Check voltage between “G24-4” wire terminal at

immobilizer control module (ICM) connector and body
ground.

Is voltage 0 V?

Go to Step 13.

Repair short to power
supply wire circuit in
communication wire
circuit.

13 Check for short of communication wire circuit

1) With immobilizer control module (ICM) connector “G24”

and ECM connector “E23” disconnected, check
resistance between “G24-3” wire terminal and “G24-4”
wire terminal at immobilizer control module (ICM)
connector.

Is resistance infinite?

Go to Step 14.

Repair short of
communication wire
circuits.

Step

Action

Yes

Immobilizer Control System: 10C-19

DTC P1622: EEPROM Error

S6JB0BA304013

Wiring Diagram
Refer to “Immobilizer Control System Wiring Circuit Diagram”

Detecting Condition and Trouble Area

Troubleshooting

1) Clear DTC(s) referring to “Diagnostic Trouble Code (DTC) Clearance”.
2) Turn the ignition switch to OFF position.
3) Check if DTC P1622 is still detected referring to “Diagnostic Trouble Code (DTC) Check”. If still detected, go to the

next step. If not, the troubleshooting is completed.

4) Replace ECM with new one referring to “Engine Control Module (ECM) Removal and Installation in Section 1C”.
5) Perform “Procedure after ECM Replacement”.

DTC P1623: Unregistered Transponder

S6JB0BA304014

Wiring Diagram
Refer to “Immobilizer Control System Wiring Circuit Diagram”

Detecting Condition and Trouble Area

Troubleshooting

14 Immobilizer control module (ICM) check

1) Check immobilizer control module (ICM) referring to

“Inspection of Immobilizer Control Module (ICM) and Its
Circuit”.

Is immobilizer control module (ICM) normal?

Replace ECM with new
one referring to “Engine
Control Module (ECM)
Removal and
Installation in Section
1C”, and then perform
“Procedure after ECM
Replacement”.