Suzuki Grand Vitara JB416 / JB420 / JB419. Manual - part 539

10C-17 Immobilizer Control System: For Petrol Engine Model

DTC P1621: Immobilizer Communication Line Error

S6JB0AA314012

Wiring Diagram
Refer to “Immobilizer Control System Wiring Circuit Diagram: For Petrol Engine Model”

Detecting Condition and Trouble Area

7

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.

8

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

No

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: For Petrol Engine Model 10C-18

Troubleshooting

Step

Action

Yes

No

1

Diagnostic Trouble Code (DTC) confirmation
1) Clear DTC(s) referring to “Diagnostic Trouble Code 

(DTC) Clearance: For Petrol Engine Model”.

2) Turn the ignition switch to OFF position.
3) Check if any DTC is detected referring to “Diagnostic 

Trouble Code (DTC) Check: For Petrol Engine Model”.

Is DTC P1621 still detected?

Go to Step 2.

The troubleshooting is 
completed.

2

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.

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: For Petrol Engine Model”.

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).

4

ECM poor connection check
1) Disconnect ECM connector “E23” referring to “Engine 

Control Module (ECM) Removal and Installation: For 
Petrol Engine Model 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).

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: For Petrol Engine Model”.

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.

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?

Go to Step 7.

Repair open in ground 
wire circuit.

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: For Petrol Engine Model”.

2) Disconnect ECM connector “E23” referring to “Engine 

Control Module (ECM) Removal and Installation: For 
Petrol Engine Model 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-19 Immobilizer Control System: For Petrol Engine Model

8

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.

9

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

No

Immobilizer Control System: For Petrol Engine Model 10C-20

DTC P1622: EEPROM Error

S6JB0AA314013

Wiring Diagram
Refer to “Immobilizer Control System Wiring Circuit Diagram: For Petrol Engine Model”

Detecting Condition and Trouble Area

Troubleshooting

1) Clear DTC(s) referring to “Diagnostic Trouble Code (DTC) Clearance: For Petrol Engine Model”.
2) Turn the ignition switch to OFF position.
3) Check if DTC P1622 is still detected referring to “Diagnostic Trouble Code (DTC) Check: For Petrol Engine 

Model”. 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: For Petrol 

Engine Model in Section 1C”.

5) Perform “Procedure after ECM Replacement: For Petrol Engine Model”.

14 Immobilizer control module (ICM) check

1) Check immobilizer control module (ICM) referring to 

“Inspection of Immobilizer Control Module (ICM) and Its 
Circuit: For Petrol Engine Model”.

Is immobilizer control module (ICM) normal?

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

Replace immobilizer 
control module (ICM) 
with new one referring 
to “Immobilizer Control 
Module (ICM) Removal 
and Installation: For 
Petrol Engine Model”.

Step

Action

Yes

No

Detecting Condition

Trouble Area

EEPROM in ECM is corrupted.

Internal failure (EEPROM corruption) of ECM