Suzuki Grand Vitara JB416 / JB420. Manual - part 415

10B-26 Body Electrical Control System: 

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

1) Connect scan tool to DLC with ignition switch turned OFF.
2) Turn ON ignition switch and clear DTC by using scan tool.
3) Start engine and run it for 1 min. or more.
4) Check DTC.

Troubleshooting

DTC detecting condition

Trouble area

BCM can not receive CAN data from TCM (A/T 
model) for longer than specified time 
continuously.

• CAN communication circuit
• BCM
• TCM (A/T model)

Step

Action

Yes

No

1

Check DTC in BCM

Is DTC U1101 (No. 1101) and DTC U1073 (No. 1073) 
detected together?

Go to “DTC U1073 (No. 
1073): Control Module 
Communication Bus 
Off”.

Go to Step 2.

2

Check each control module connectors
1) Check connection of connectors of all control modules 

communicating by means of CAN.

2) Recheck BCM for DTC.

Is DTC U1101 (No. 1101) detected?

Go to Step 3.

Intermittent trouble. 
Check for intermittent 
referring to “Intermittent 
and Poor Connection 
Inspection in Section 
00”.

3

CAN communication circuit check
1) Turn ignition switch to OFF position.
2) Disconnect connectors of BCM and TCM 

communicating by means of CAN.

3) Check CAN communication circuit between control 

modules for open, short and high resistance.

Is each CAN communication circuit in good condition?

Go to Step 4.

Repair circuit.

4

DTC Check
1) Turn ignition switch to OFF position.
2) Connect connectors to BCM and TCM.
3) Check DTC for ECM.

 Is DTC P1678 detected by ECM?

Substitute a known-
good BCM and recheck.

Check TCM power and 
ground circuit. If circuit 
is OK, substitute a 
known-good TCM and 
recheck.

Body Electrical Control System:  10B-27

DTC U1144 (No. 1144): Lost Communication with Keyless Start Control Module

S5JB0AA204018

Wiring Diagram

WHT

RED

WHT

RED

G44-18

G44-19

G44

[A]

[B]

[C]

[H]

[G]

1

2

3

4

5

6

7

8

9

10

11

14

15

16
36

34 33 32

30 29

24 23

37

18

19

20

G28-8

G28-10

WHT/BLU

WHT/BLU

WHT/RED

WHT/RED E23-4

E23-19

WHT

RED E03-12

E03-10

E03-6

E03-8

WHT

RED

E92-17

E92-7

WHT

RED

E91-22
E91-23

WHT

RED

RED

G31-1
G31-3

G31-4

6

5

16 15 14 13 12 11

4 3

24 23

21

22

10 9

8

7

2

1

19

20

18 17

E92

2 1

E23

3

4

18

19

5

6

7

10

11

17

20

47 46

49

50

51

21

22

52

16

25

9

24

14

29

55

57

5453

59

60

58

26

27

28

15
30

56

48

32 31

34

35

36

37

40

42

3938

44

45

43

41

33

12

13

23

8

1

2

3

4

5

6

7

8

9

10

11

17

1615141312

2221201918

G28

[F]

G31

E91

1

2

3

4

7

8

9

10

11

14

15

16
36

34

35

24 23

21

22

28 27

25

26

37

39 38

40

18 17

13 12

19

20

1

2

3

10

11

12

16

17

18

15 14 13

19

20

21

25

26

5

6

[E]

[D]

E03

15
16
17
18
19
20
21
22
23
24
25

2
3
4
5
6
7
8
9

10
11
12

1

13

14

26

8 7 6 5 4 3 2 1

9

10

11

12

13

14

15

16

G31-2

WHT

1

2

3

4

9

5

6

7

8

I5JB0AA50017-03

[A]: Keyless start control module connector (viewed from harness side)

1. Keyless start control module

[B]: ECM connector (viewed from harness side)

2. TCM (A/T model)

[C]: TCM connector (viewed from harness side)

3. 4WD control module (if equipped)

[D]: DLC (viewed from harness side)

4. BCM

[E]: ABS hydraulic unit/control module connector (viewed from harness side)

5. DLC

[F]: Combination meter connector (viewed from harness side)

6. ECM

[G]: 4WD control module connector (viewed from harness side)

7. ABS hydraulic unit/control module

[H]: BCM connector (viewed from harness side)

8. Combination meter
9. Junction connector

10B-28 Body Electrical Control System: 

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

1) Clear DTC referring to “DTC Clearance”.
2) Start engine and run it for 1 min. or more.
3) Check DTC referring to “DTC Check”.

Troubleshooting

DTC detecting condition

Trouble area

BCM can not receive data sent by CAN from keyless start 
control module for longer than specified time continuously.

• CAN communication circuit
• Keyless start control module
• BCM

Step

Action

Yes

No

1

Check DTC in BCM

Is DTC U1144 (No. 1144) and DTC U1073 (No. 1073) 
detected together?

Go to “DTC U1073 (No. 
1073): Control Module 
Communication Bus 
Off”.

Go to Step 2.

2

Check each control module connectors
1) Check connection of connectors of all control modules 

communicating by means of CAN.

2) Recheck BCM for DTC.

Is DTC U1144 (No. 1144) detected?

Go to Step 3.

Intermittent trouble. 
Check for intermittent 
referring to “Intermittent 
and Poor Connection 
Inspection in Section 
00”.

3

CAN communication circuit check
1) Turn ignition switch to OFF position.
2) Disconnect connectors of BCM and keyless start control 

module communicating by means of CAN.

3) Check CAN communication circuit between control 

modules for open, short and high resistance.

Is each CAN communication circuit in good condition?

Go to Step 4.

Repair circuit.

4

DTC Check
1) Turn ignition switch to OFF position.
2) Connect connectors to BCM and keyless start control 

module.

3) Check DTC for ECM.

Is DTC P1618 detected by ECM?

Substitute a known-
good BCM and recheck.

Check keyless start 
control module power 
and ground circuit. If 
circuit is OK, substitute 
a known-good keyless 
start control module and 
recheck.

Body Electrical Control System:  10B-29

Inspection of BCM and its Circuits

S5JB0AA204017

BCM and its circuits can be checked at BCM wiring couplers by measuring voltage and resistance.

CAUTION

!

 

BCM cannot be checked by itself. It is strictly prohibited to connect voltmeter or ohmmeter to BCM 
with couplers disconnected from it.

 

Voltage Check

1) Disconnect negative cable (–) at battery.
2) Remove steering column hole cover from instrument panel.
3) Check voltage at each terminal number of couplers connected.

For connector and terminal number, refer to “Connector Layout Diagram of BCM”.

NOTE

• As each terminal voltage is affected by the battery voltage, confirm that it is 11 V or more when 

ignition switch is ON.

• Voltage with asterisk (*) can not be measured by voltmeter because it is pulse signal.

Check it with oscilloscope if necessary.

 

BCM connector “G30”

1

1

I5JB0AA20012-01

1. BCM

Terminal

Circuit

Normal voltage

Condition

G30-1

Power source (IG)

10 – 14 V

Ignition switch is at ON position

0 V

Ignition switch is at any position other than ON 
position

G30-2

Power source (ACC)

10 – 14 V

Ignition switch is at ACC or ON position

0 V

Ignition switch is at any position other than ACC or 
ON position

G30-3

Key reminder switch

10 – 14 V

Ignition key is inserted to ignition key cylinder

0 V

Ignition key is pulled out from ignition key cylinder

G30-4

Serial communication line for 
HVAC control module

*0 – 1 V

↑↓

10 – 14 V

Refer to “Reference waveform No. 1: ”

G30-5

Serial communication line for 
information display and HVAC 
control module

*0 – 1V

↑↓

10 – 14 V

Refer to “Reference waveform No. 2: ” 

G30-6

Rear wiper switch

*0 – 1 V

↑↓

10 – 14 V

Refer to “Reference waveform No. 3: ” 

0 V

Ignition switch is at ON position and rear wiper 
switch is at ON position