INFINITI QX56 2008 Factory Service Manual

BCS-6
< FUNCTION DIAGNOSIS >[BCM]
BODY CONTROL SYSTEM
Component Parts Location
INFOID:0000000001696403
• BCM M18, M19, M20 (view wit h instrument panel removed)
LEIA0068E
Revision: March 2010 2008 QX56

BCS
COMBINATION SWITCH READING SYSTEMBCS-7
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COMBINATION SWITCH
READING SYSTEM
System DiagramINFOID:0000000001696404
System DescriptionINFOID:0000000001696405
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: March 2010 2008 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: March 2010 2008 QX56

BCS
COMBINATION SWITCH READING SYSTEMBCS-9
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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 “1 E” 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: March 2010 2008 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:0000000001696406
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
ONON
2O NON OFF
3O NOFF OFF
4 OFFOFFOFF
5O FF OFF ON
6 OFFONON
7 OFFONOFF
ALMIA0262ZZ
Revision: March 2010 2008 QX56

BCS
COMBINATION SWITCH READING SYSTEMBCS-11
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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: March 2010 2008 QX56

BCS-12
< FUNCTION DIAGNOSIS >[BCM]
SIGNAL BUFFER SYSTEM
SIGNAL BUFFER SYSTEM
System DiagramINFOID:0000000001696407
System DescriptionINFOID:0000000001696408
OUTLINE
BCM has the signal transmission function that output
s/transmits each input/received signal to each unit.
Signal transmission function list
ALMIA0263GB
Signal nameInputOutputDescription
Oil pressure switch signal IPDM E/R (CAN) Combination meter (CAN)Transmits the received oil pres-
sure switch signal via CAN
communication.
Revision: March 2010
2008 QX56

BCS
POWER CONSUMPTION CONTROL SYSTEMBCS-13
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POWER CONSUMPTION CONTROL SYSTEM
System DiagramINFOID:0000000001696409
System DescriptionINFOID:0000000001696410
OUTLINE
• BCM incorporates a power consumpt
ion control function that reduces the power consumption according to
the vehicle status.
• BCM switches the status (control mode) by itself with the power saving control function. It performs the sleep
request to each unit IPDM 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 following 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: March 2010 2008 QX56

BCS-14
< FUNCTION DIAGNOSIS >[BCM]
POWER CONSUMPTION CONTROL SYSTEM
Sleep condition
Wake-up operation
• BCM transmits sleep wake up signal (wake up) to each unit when any condition listed below is established,
and then goes into normal mode from low power consumption mode.
• Each unit starts transmissions with CAN communication by receiving sleep wake up signals. Each unit trans- mits wake up signals to BCM with CAN communication to convey the start of CAN communication.
Wake-up condition
CAN sleep condition BCM sleep condition
• Receiving the sleep-ready signal (ready) from all units
• Ignition switch: OFF
• Vehicle security system alarm: No operation
• Warning lamp: No operation
• Warning chime: No operation
• Stop lamp switch: OFF
• Key switch status: No change for 2 seconds
• Hazard warning lamp: No operation
•Exterior lamp: OFF
• Door lock status: No change for 2 seconds
• CONSULT-III communication status: No communication
• Door switch status: No change for 2 seconds The controls only BCM are completed.
(Interior room lamp battery saver: Time out etc.)
BCM wake-up condition
• Ignition switch: OFF → ACC or ON
• Stop lamp switch: ON (Depress brake pedal)
• Any door switch: OFF → ON
• Lighting switch: OFF → 1ST or PASS
• Hazard switch: OFF → ON
• Back door opener switch OFF → ON
• Remote keyless entry receiver: Receiving
• Intelligent Key unit: Receiving
Revision: March 2010 2008 QX56

BCS
POWER CONSUMPTION CONTROL SYSTEMBCS-15
< FUNCTION DIAGNOSIS > [BCM]
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Component Parts LocationINFOID:0000000001696411
1. Steering column
(view with instru-
ment panel removed) 2. BCM M18, M19, M20 3. Combination meter M24
4. IPDM E/R E119, E120, E121, E122, E123, E124 5. Intelligent Key unit M70 (view with in-
strument panel removed)
ALMIA0418ZZ
Revision: March 2010 2008 QX56