Suzuki Grand Vitara JB416 / JB420 (ESP model). Service manual - part 105

10C-5 Immobilizer Control System: 

DTC P1615: Steering Lock Unit Communication Error (for Vehicle with Keyless Start System)

S5JB0EA304009

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

Circuit Description
When the transponder code in the ignition key is registered in ECM, the remote controller ID code is registered in both 
ECM and keyless start control module at the same time. This DTC is detected only in case that the remote controller 
ID code cannot be registered in both ECM and keyless start control module when the transponder code in the ignition 
key is registered in ECM.

NOTE

• Perform the troubleshooting for DTC P1618 first if both DTC P1615 and P1618 are detected at the 

same time.

• After replacing ECM, be sure to register the transponder code in the ignition key with ECM referring 

to “Registration of the Ignition Key in related manual”. After replacing the keyless start control 
module of the vehicle equipped with the keyless start system, be sure to perform “Registration of 
the Ignition Key in related manual”.

 

Detecting Condition and Trouble Area

Troubleshooting

Detecting Condition

Trouble Area

• While registering the transponder code in ECM, the 

keyless start control module sent a signal to ECM 
indicating that the remote controller ID code could not 
be registered.

• The remote controller ID code could not be registered in 

the keyless start control module or ECM. And, the 
registration of the transponder code in ECM was 
terminated forcibly.

• Wire circuits between steering lock unit and keyless 

start control unit open or shorted

• CAN communication wire circuits faulty
• Steering lock unit faulty
• Keyless start control module faulty
• ECM faulty

Step

Action

Yes

No

1

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

(DTC) Clearance in related manual”.

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

Trouble Code (DTC) Check in related manual”.

Is DTC P1615 still detected?

Go to Step 2.

The troubleshooting is 
completed.

2

Registration of the ignition key
1) Turn the ignition switch to OFF position.
2) Turn the ignition switch to ON position, and register the 

transponder code in the transponder in the ignition key 
with ECM referring to “Registration of the Ignition Key in 
related manual”.

Was it possible to register the ignition key (transponder 
code) in ECM?

The troubleshooting is 
completed.

Go to Step 3.

3

Diagnostic Trouble Code (DTC) check
1) Check if any DTC is detected referring to “Diagnostic 

Trouble Code (DTC) Check in related manual”.

Is any DTC detected?

Go to Step 4.

Replace ECM with a 
known-good one and 
recheck.

Immobilizer Control System:  10C-6

4

Diagnostic Trouble Code (DTC) check

Is any DTC other than P1615 detected in Step 3?

Perform the 
troubleshooting 
referring to the 
corresponding 
flowchart.

Go to Step 5.

5

Steering lock unit check
1) Turn on the engine start knob of the keyless start 

system.

Is the engine start knob at ON position?

Replace the steering 
lock unit with a known-
good one and recheck.

Go to Step 6.

6

Steering lock unit operation check
1) Check the steering lock unit for operation referring to 

“Ignition Switch Inspection in Section 9C”.

Does the engine start knob operate as specified?

Go to Step 7.

Replace the steering 
lock unit referring to 
“Steering Lock 
Assembly (Ignition 
Switch) Removal and 
Installation in Section 
6B in related manual”.

7

Check for open in wire circuits between steering lock 
unit and keyless start control module
1) Disconnect steering lock unit connector “G22” and 

keyless start control module connector “G42”.

2) Measure resistance at the following connector terminals.

• Between “G22-3” terminal of steering lock unit 

connector and “G42-20” terminal of keyless start 
control module connector.

• Between “G22-7” terminal of steering lock unit 

connector and “G42-29” terminal of keyless start 
control module connector.

• Between “G22-8” terminal of steering lock unit 

connector and “G42-30” terminal of keyless start 
control module connector.

Is each resistance 1 

Ω

 or less?

Go to Step 8.

Repair open or high 
resistance in 
malfunctional wire 
circuit.

8

Check for short of wire circuits between steering lock 
unit and keyless start control module
1) Measure resistance at the following connector terminals.

• Between “G22-3”, “G22-7” and “G22-8” terminal of 

steering lock unit connector.

• Between “G42-20”, “G42-29” and “G42-30” terminal of 

keyless start control module.

Is each resistance infinity?

Go to Step 9.

Make sure of insulation 
of each wire circuit.

Step

Action

Yes

No

10C-7 Immobilizer Control System: 

DTC P1616: Unregistered Keyless Start Control Module (for Vehicle with Keyless Start System)

S5JB0EA304010

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

Circuit Description
P1616 is detected when ECM detects different ID codes registered in ECM and keyless control module after turning 
engine start knob to ON position. Normally, when keyless start control module is replaced with new one, ECM 
automatically registers the applicable code in keyless start control module after turning ignition switch to ON position. 
However, when keyless start control module is replaced with used one, ECM does not automatically register the 
applicable code in keyless start control module even if ignition switch is turned to ON position.

Detecting Condition and Trouble Area

9

Check for short to ground wire circuit in wire circuits 
between steering lock unit and keyless start control 
module
1) Measure resistance at the following connector terminals.

• Between “G22-3” terminal of steering lock unit 

connector and vehicle body ground.

• Between “G22-7” terminal of steering lock unit 

connector and vehicle body ground.

• Between “G22-8” terminal of steering lock unit 

connector and vehicle body ground.

• Between “G42-20” terminal of keyless start control 

module connector and vehicle body ground.

• Between “G42-29” terminal of keyless start control 

module connector and vehicle body ground.

• Between “G42-30” terminal of keyless start control 

module connector and vehicle body ground.

Is each resistance infinity?

Go to Step 10.

Repair short to ground 
wire circuit in 
malfunctional wire 
circuit.

10 Check for short to power supply wire circuit in wire 

circuits between steering lock unit and keyless start 
control module
1) Measure voltage at the following connector terminals 

with ignition switch turned ON.
• Between “G22-3” terminal of steering lock unit 

connector and vehicle body ground.

• Between “G22-7” terminal of steering lock unit 

connector and vehicle body ground.

• Between “G22-8” terminal of steering lock unit 

connector and vehicle body ground.

• Between “G42-20” terminal of keyless start control 

module connector and vehicle body ground.

• Between “G42-29” terminal of keyless start control 

module connector and vehicle body ground.

• Between “G42-30” terminal of keyless start control 

module connector and vehicle body ground.

Is each voltage 0 – 1 V?

Replace keyless start 
control module with a 
known-good one and 
recheck. If DTC P1615 
is still detected, replace 
ECM with a known-good 
one and recheck.

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

Step

Action

Yes

No

Detecting Condition

Trouble Area

ECM detects different ID codes registered in ECM and 
keyless control module.

• Keyless start control unit faulty
• ECM faulty

Immobilizer Control System:  10C-8

Troubleshooting

DTC P1618: Keyless Start Control Module CAN Communication Error (for Vehicle with Keyless Start 
System)

S5JB0EA304011

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

Detecting Condition and Trouble Area

Step

Action

Yes

No

1

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

(DTC) Clearance in related manual”.

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

Trouble Code (DTC) Table”.

Is DTC P1616 still detected?

Go to Step 2.

The troubleshooting is 
completed.

2

Registration of the ignition key
1) Clear DTC referring to “Diagnostic Trouble Code (DTC) 

Clearance in related manual”.

2) Register the transponder code in the transponder in the 

ignition key with ECM referring to “Registration of the 
Ignition Key in related manual”.

Was it possible to register the ignition key (transponder 
code) in ECM?

Go to Step 3.

Go to Step 4.

3

Keyless start system operation check
1) Start engine using keyless start system.

Does engine start?

The troubleshooting is 
completed.

Check if any DTC is 
detected by ECM. If 
detected, perform the 
troubleshooting 
referring to the 
corresponding 
flowchart.

4

Diagnostic Trouble Code (DTC) check
1) Check ECM for DTC referring to “Diagnostic Trouble 

Code (DTC) Check in related manual”.

Are DTC P1618 and/or P1615 detected other than P1616?

Go to DTC P1618 
troubleshooting.

Go to DTC P1615 
troubleshooting.

Detecting Condition

Trouble Area

Reception error of communication data for keyless start 
control module is detected for longer than specified time 
continuously.

• CAN communication wire circuits faulty
• Steering angle sensor (if equipped) faulty
• Keyless start control module faulty
• 4WD control module (if equipped) faulty
• TCM (if equipped) faulty
• BCM faulty
• ABS/ESP

® control module faulty

• Combination meter faulty
• ECM faulty