Suzuki Grand Vitara JB416 / JB420 / JB419. Manual - part 533

10B-33 Body Electrical Control System: 

Inspection of BCM and Its Circuits

S6JB0AA204017

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

Ignition switch signal (IG ON)

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

Body Electrical Control System:  10B-34

BCM connector “G31”

G30-7

Rear wiper INT 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 INT position

G30-8

—

—

—

G30-9

Front fog light switch (if equipped)

10 – 14 V

Lighting switch is at CLEARANCE position and 
front fog light switch is at ON position

0 V

Lighting switch is at CLEARANCE position and 
front fog light switch is at OFF position

G30-10 Lighting switch (HEAD)

10 – 14 V

Lighting switch is at any position other than HEAD 
position

0 V

Lighting switch is at HEAD position

G30-11 Lighting switch (CLEARANCE)

10 – 14 V

Lighting switch is at OFF position

0 V

Lighting switch is at any position other than OFF 
position

G30-12 Ground for BCM

0 V

Ignition switch is at each position

G30-13

—

—

—

G30-14

—

—

—

G30-15

—

—

—

G30-16 Theft deterrent light

10 – 14 V

Theft deterrent light is not lit up

0 V

Theft deterrent light is lit up

G30-17

—

—

—

G30-18

—

—

—

G30-19 Serial communication line of SDM

*0 – 1 V

↑↓

4 – 6 V

Refer to “Reference waveform No. 4: ”

G30-20

—

—

—

G30-21

Lighting switch (AUTO) (if 
equipped)

10 – 14 V

Lighting switch is at other than AUTO position

0 V

Lighting switch is at AUTO position

G30-22

Vehicle speed signal output (if 
equipped)

*0 – 1 V

↑↓

10 – 14 V

Refer to “Reference waveform No. 5: ”

G30-23

—

—

—

G30-24

—

—

—

Terminal

Circuit

Normal voltage

Condition

Terminal

Circuit

Normal voltage

Condition

G31-1

CAN communication line (high) for 
each control module

*2.5 – 3.6 V

Refer to “Reference waveform No. 6: ”

G31-2

CAN communication line (high) for 
DLC

*2.5 – 3.6 V

G31-3

CAN communication line (low) for 
each control module

*1.6 – 2.5 V

G31-4

CAN communication line (low) for 
DLC

*1.6 – 2.5 V

G31-5

—

—

—

G31-6

—

—

—

G31-7

Brake fluid level switch

*5 – 12 V

Refer to “Reference waveform No. 7: ”

0 V

Ignition switch is at ON position and brake fluid 
level is lower than MIN level

G31-8

Parking brake switch

*5 – 12 V

Refer to “Reference waveform No. 7: ”

0 V

Ignition switch is at ON position and parking brake 
lever is pulled up

G31-9

Oil pressure switch

*6 – 14 V

Refer to “Reference waveform No. 8: ”

0 V

Ignition switch is at ON position and engine is at 
stop

G31-10 Generator “L” terminal

10 – 14 V

Engine is running

0 V

Ignition switch is at ON position

10B-35 Body Electrical Control System: 

G31-11

—

—

—

G31-12 Tail light relay control

10 – 14 V

Lighting switch is at OFF position

0 V

Lighting switch is at any position other than OFF 
position

G31-13 Rear wiper control

10 – 14 V

Ignition switch is at ON position and rear wiper is 
not in operation

0 V

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

G31-14

Rear end door window defogger 
control

10 – 14 V

Engine is running and rear end door window 
defogger is not in operation

0 V

Engine is running and rear end door window 
defogger is in operation

G31-15 Horn control

10 – 14 V

Horn is not in operation

0 V

Horn is in operation

G31-16 DRL control (if equipped)

10 – 14 V

Engine is running and lighting switch is at 
CLEARANCE or OFF position

0 V

Engine is running and lighting switch is at HEAD 
position

G31-17 Front fog light control (if equipped)

10 – 14 V

Lighting switch is at CLEARANCE position and 
front fog light switch is at OFF position

0 V

Lighting switch is at CLEARANCE position and 
front fog light switch is at ON position

G31-18

Power supply for keyless entry 
receiver (if equipped)

4 – 6 V

Ignition switch is at ON position

G31-19

Signal for keyless entry receiver (if 
equipped)

*0 – 1 V

↑↓

4 – 6 V

Refer to “Reference waveform No. 9: ”

G31-20

Ground for keyless entry receiver 
(if equipped)

0 V

Ignition switch is at each position

G31-21

Sensor ground for outside air 
temperature sensor

0 V

Ignition switch is at each position

G31-22

Sensor ground for auto light 
sensor (if equipped)

0 V

Ignition switch is at each position

G31-23

Auto-on headlight sensor (if 
equipped)

0.2 V

Ignition switch is at ON position and cover auto-on 
headlight sensor lens by hand

3 – 4 V

Ignition switch is at ON position and light auto-on 
headlight sensor lens by 100 W lights

G31-24 Outside air temperature sensor

About 1.5 V

Ignition switch is at ON position and outside air 
temperature approx. 20 

°C (68 °F)

G31-25

Power supply for auto light sensor 
(if equipped)

4 – 6 V

Ignition switch is at ON position

G31-26 Manual door lock switch (Unlock)

4 – 6 V

Manual door lock switch is at any position other 
than unlock position

0 V

Manual door lock switch is at unlock position

G31-27 Manual door lock switch (Lock)

4 – 6 V

Manual door lock switch is at any position other 
than lock position

0 V

Manual door lock switch is at lock position.

G31-28

Power/Normal mode switch (A/T 
model)

4 – 6 V

Ignition switch is at ON position and Power/Normal 
mode switch is at ON position

0 V

Ignition switch is at ON position and Power/Normal 
mode switch is at OFF position

G31-29

—

—

—

G31-30

—

—

—

G31-31

—

—

—

G31-32

—

—

—

G31-33

—

—

—

G31-34

Turn signal / hazard warning relay 
control

0 V

Hazard warning switch is at ON position

10 – 14 V

Hazard warning switch is at OFF position

G31-35 Serial communication line of DLC

7 – 12 V

Ignition switch is at ON position

Terminal

Circuit

Normal voltage

Condition

Body Electrical Control System:  10B-36

BCM connector “G32”

G31-36

Driver side door key cylinder 
switch (Unlock)

10 – 14 V

Driver side key cylinder switch is at any position 
other than unlock position

0 V

Driver side key cylinder switch is at unlock position

G31-37

Driver side door key cylinder 
switch (lock)

10 – 14 V

Driver side key cylinder switch is at any position 
other than lock position

0 V

Driver side key cylinder switch is at lock position

G31-38

Door switch (rear end door and 
other than driver side door)

10 – 14 V

Rear right and left side door, passenger side door 
and rear end door are closed

0 V

Any one of the door is opened (except driver side 
door)

G31-39 Driver side door switch

10 – 14 V

Driver side door is closed

0 V

Driver side door is opened

G31-40 Driver seat belt switch

*5 – 12 V

Refer to “Reference waveform No. 7: ”

0 V

Ignition switch is at ON position and driver seat 
belt is unfastened

Terminal

Circuit

Normal voltage

Condition

Terminal

Circuit

Normal voltage

Condition

G32-1

Ground for BCM

0 V

Ignition switch is at each position

G32-2

Rear door lock actuator control 
(Unlock)

10 – 14 V

Unlock signal is output for rear door lock actuators

0 V

Unlock signal is not output for rear door lock 
actuators

G32-3

Door lock actuator control (Lock)

10 – 14 V

Lock signal is output for all door lock actuators

0 V

Lock signal is not output for all door lock actuators

G32-4

—

—

—

G32-5

Power supply for door lock 
actuator

10 – 14 V

Ignition switch is at each position

G32-6

—

—

—

G32-7

Rear end door lock actuator 
control (Unlock)

10 – 14 V

Unlock signal is output for rear end door lock 
actuator

0 V

Unlock signal is not output for rear end door lock 
actuator

G32-8

Driver side door lock actuator 
control (Unlock)

10 – 14 V

Unlock signal is output for driver side door lock 
actuator

0 V

Unlock signal is not output for driver side door lock 
actuator

G32-9

Passenger side door lock actuator 
control (Unlock)

10 – 14 V

Unlock signal is output for passenger side door 
lock actuator

0 V

Unlock signal is not output for passenger side door 
lock actuator

G32-10

Door lock actuator control (Dead 
lock cancel) (if equipped)

10 – 14 V

Driver side key cylinder is turned to unlock position

0 V

Driver side key cylinder is at any position other 
than unlock position

G32-11

Door lock actuator control (Dead 
lock set) (if equipped)

10 – 14 V

Driver side key cylinder is turned to lock twice 
within 3 seconds

0 V

Driver side key cylinder is at any position other 
than lock position

G32-12

Headlight high beam monitor 
signal

10 – 14 V

Lighting switch is at HEAD position and dimmer 
switch is at low beam position

0 V

Lighting switch is at HEAD position and dimmer 
switch is at high beam position

G32-13 Power supply for BCM

10 – 14 V

Ignition switch is at each position

G32-14

—

—

—

G32-15 Interior light control

10 – 14 V

Interior light switch is at DOOR position and 
interior light is not lit up

0 V

Interior light switch is at DOOR position and 
interior light is lit up