2009 INFINITI QX56 200

BCS-6
< FUNCTION DIAGNOSIS >[BCM]
BODY CONTROL SYSTEM
Component Parts Location
INFOID:0000000003776378
 BCM M18, M19, M20 (view wit h instrument panel removed)
LEIA0068E
Revision: December 20092009 QX56

BCS
COMBINATION SWITCH READING SYSTEMBCS-7
< FUNCTION DIAGNOSIS > [BCM]
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COMBINATION SWITCH READING SYSTEM
System DiagramINFOID:0000000003776379
System DescriptionINFOID:0000000003776380
OUTLINE
 BCM reads the status of the combination switch (light, turn signal, wiper and washer) and recognizes the
status of each switch.
 BCM is a combination of 5 output terminals (OUTPUT 1 - 5) and 5 input terminals (INPUT 1 - 5). It reads a
maximum of 20 switch status.
COMBINATION SWITCH MATRIX
LIIA0757E
Revision: December 20092009 QX56

BCS-8
< FUNCTION DIAGNOSIS >[BCM]
COMBINATION SWITCH READING SYSTEM
Combination switch circuit
Combination switch INPUT-OUTPUT system list
NOTE:
Headlamp has a dual system switch.
COMBINATION SWITCH READING FUNCTION
Description
 BCM reads the status of the combination switch at 10 ms interval normally.
NOTE:
BCM reads the status of the combination switch at 20 ms interval when BCM is controlled at low power con-
sumption control mode.
 BCM operates as follows and judges the status of the combination switch.
- INPUT 1 - 5 outputs the voltage waveforms of 5 systems simultaneously.
- It operates the transistor on OUTPUT side in the following order: OUTPUT 5 → 4 → 3 → 2 → 1.
System OUTPUT 1 OUTPUT 2 OUTPUT 3 OUTPUT 4 OUTPUT 5
INPUT 1 — FR WASHER FR WIPER LOW TURN LH TURN RH
INPUT 2 FR WIPER HI — FR WIPER INT PASSING HEADLAMP 1
INPUT 3 INT VOLUME 1 RR WASHER — HEADLAMP 2 HI BEAM
INPUT 4 RR WIPER INT INT VOLUME 3 AUTO LIGHT — TAIL LAMP
INPUT 5 INT VOLUME 2 RR WIPER — FR FOG —
LIIA0760E
JPMIA0067GB
Revision: December 20092009 QX56

BCS
COMBINATION SWITCH READING SYSTEMBCS-9
< FUNCTION DIAGNOSIS > [BCM]
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- The voltage waveform of INPUT corresponding to the
formed circuit changes according to the operation of
the transistor on OUTPUT side if any (1 or more) switches are ON.
- It reads this change of the voltage as the status signal of the combination switch.
Operation Example
In the following operation example, the combination of t he status signals of the combination switch is replaced
as follows: INPUT 1 - 5 to “1 - 5” and OUTPUT 1 - 5 to “A - E”.
Example 1: When a switch (TURN RH switch) is turned ON
 The circuit between INPUT 1 and OUTPUT 5 is formed when the TURN RH switch is turned ON.
 BCM detects the combination switch status signal “1E” when the signal of OUTPUT 5 is input to INPUT 1.
 BCM judges that the TURN RH switch is ON when the signal “1E” is detected.
Example 2: When some switches (turn RH s witch, front wiper LO switch) are turned ON
JPMIA0068GB
ALMIA0260GB
Revision: December 20092009 QX56

BCS-10
< FUNCTION DIAGNOSIS >[BCM]
COMBINATION SWITCH READING SYSTEM
 The circuits between INPUT 1 and OUTPUT 5 and between INPUT 1 and OUTPUT 3 are formed when the
TURN RH switch and FR WIPER LOW switch are turned ON.
 BCM detects the combination switch status signal “1CE” when the signals of OUTPUT 3 and OUTPUT 5 are
input to INPUT 1.
 BCM judges that the TURN RH switch and FR WIPE R LOW switch are ON when the signal “1CE” is
detected.
WIPER INTERMITTENT DIAL POSITION SETTIN G (FRONT WIPER INTERMITTENT OPERATION)
BCM judges the wiper intermittent dial 1 - 7 by the status of INT VOLUME 1, 2 and 3 switches.
Component Parts LocationINFOID:0000000003776381
ALMIA0261GB
Wiper intermittent
dial position Intermittent
operation delay
interval INT VOLUME switch ON/OFF status
INT VOLUME 1 switch INT VOLUME 2 switch INT VOLUME 3 switch
1 Short
↑
↓
Long ON ON ON
2ONONOFF
3ONOFFOFF
4 OFF OFF OFF
5OFFOFFON
6 OFF ON ON
7 OFF ON OFF
ALMIA0262ZZ
Revision: December 20092009 QX56

BCS
COMBINATION SWITCH READING SYSTEMBCS-11
< FUNCTION DIAGNOSIS > [BCM]
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1. BCM M18, M19, M20 (view with in-
strument panel removed) 2. Combination switch (lighting and
turn signal switch) M28 3. Combination switch (wiper and
washer switch) M28
Revision: December 20092009 QX56

BCS-12
< FUNCTION DIAGNOSIS >[BCM]
SIGNAL BUFFER SYSTEM
SIGNAL BUFFER SYSTEM
System DiagramINFOID:0000000003776382
System DescriptionINFOID:0000000003776383
OUTLINE
BCM has the signal transmission function that output
s/transmits each input/received signal to each unit.
Signal transmission function list
ALMIA0263GB
Signal name Input Output Description
Oil pressure switch signal IPDM E/R (CAN) Combination meter (CAN) Transmits the received oil pres-
sure switch signal via CAN
communication.
Revision: December 20092009 QX56

BCS
POWER CONSUMPTION CONTROL SYSTEMBCS-13
< FUNCTION DIAGNOSIS > [BCM]
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POWER CONSUMPTION CONTROL SYSTEM
System DiagramINFOID:0000000003776384
System DescriptionINFOID:0000000003776385
OUTLINE
 BCM incorporates a power consumpt
ion control function that reduces the power consumption according to
the vehicle status.
 BCM switches the status (control m ode) by itself with the power saving control function. It performs the sleep
request to each unit (PDM E/R, combination meter and In telligent Key unit) that operates with the ignition
switch OFF.
Normal mode (wake-up)- CAN communication is normally performed with other units
- Each control with BCM is operating properly
CAN communication sleep mode (CAN sleep)- CAN transmission is stopped
- Control with BCM only is operating
Low power consumption mode (BCM sleep)- Low power consumption control is active
- CAN transmission is stopped
LOW POWER CONSUMPTION CONTROL WITH BCM
BCM reduces the power consumption with the follo wing operation in the low power consumption mode.
 The reading interval of the each switches changes from 10 ms interval to 20 ms interval.
Sleep mode activation
 BCM receives the sleep-ready signal (ready) from IPDM E/R, combination meter and Intelligent Key unit via
CAN communication.
 BCM transmits the sleep wake up signal (sleep) to each unit when all of the CAN sleep conditions are ful-
filled.
 Each unit stops the transmission of CAN communicati on with the sleep wake up signal. BCM is in CAN com-
munication sleep mode.
 BCM is in the low power consumption mode and perform the low power consumption control when all of the
BCM sleep conditions are fulfilled with CAN sleep condition.
AWMIA0082GB
Revision: December 20092009 QX56