2011 INFINITI QX56 4WD

SYSTEMBRC-29
< SYSTEM DESCRIPTION > [WITH VDC]
C
D
E
G H
I
J
K L
M A
B
BRC
N
O P
side/decel G- sensor and wheel sensor, vehicle drivi ng conditions (conditions of understeer or oversteer) are
judged and vehicle stability is improved by brake forc e control on all 4 wheels and engine output control.
 Control unit portion automatically improves driving st ability by performing brake force control as well as
engine output control, by transmitting drive signal to actuator portion according to difference between target
side slip amount and vehicle side slip amount
 VDC function can be switched to non-operational status (OFF) by operating VDC OFF switch. In this case,
VDC OFF indicator lamp turns ON.
 VDC function is not operate when 4WD mode is “4L”. (Models with 4WD system)
 VDC warning lamp blinking while VDC function is in oper ation and indicates to the driver that the function is
in operation.
 Slight vibrations are felt on the brake pedal and t he operation noises occur, when VDC function operates.
This is not a malfunction because it is caus ed by VDC function that is normally operated.
 CONSULT-III can be used to diagnose the system diagnosis.
 Fail-safe function is adopted. When a malfunction occurs in VDC function, the control is suspended for VDC
function, TCS function, hill start as sist function and brake limited slip di fferential (BLSD) function. The vehi-
cle status becomes the same as m odels without VDC function, TCS functi on, hill start assist function and
brake limited slip differential (BLSD) function. Ho wever, ABS function and EBD function are operated nor-
mally. Refer to BRC-25, "
Fail-safe".
NOTE:
VDC has the characteristic as de scribed here, but it is not the device that helps reckless driving.
SYSTEM DIAGRAM
NOTE:
Transfer control unit is applied to models with 4WD system.
INPUT SIGNAL AND OUTPUT SIGNAL
JPFIC0133GB
JPFIC0183GB
Revision: 2010 May2011 QX56

BRC-30
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
Major signal transmission between each unit via communication lines is shown in the following table.
*1: Communication line between yaw rate/side/decal G s
ensor and ABS actuator and electric unit (control unit)
*2: Models with 4WD system
OPERATION CHARACTERISTICS
VDC Function That Prevents Oversteer Tendency
 During a cornering, brake force (brake fluid pressure) is applied on front wheel and rear wheel on the outer side of turn. Moment directing towards the outer side of turn is generated. Oversteer is prevented.
 Changing driving lane on a slippery road, when oversteer tendency is judged large, engine output is con- trolled as well as brake force (brake fluid pr essure) of 4 wheels. Oversteer tendency decreases.
VDC Function That Prevents Understeer Tendency
Component Signal description
Yaw rate/side/decel G sensor Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via com-
munication line
*1.
 Yaw rate signal
 Side G sensor signal
 Decel G sensor signal
ECM Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Accelerator pedal position signal
 Engine speed signal
Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 Target throttle position signal
TCM Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Shift position signal
Transfer control unit
*2Mainly transmits the following si gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Current 4WD mode signal
Steering angle sensor Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Steering angle sensor signal
Combination meter Mainly receives
the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 VDC warning lamp signal
 VDC OFF indicator lamp
JPFIC0135GB
JPFIC0136GB
Revision: 2010 May2011 QX56

SYSTEMBRC-31
< SYSTEM DESCRIPTION > [WITH VDC]
C
D
E
G H
I
J
K L
M A
B
BRC
N
O P
 During a cornering, brake force (brake fluid pressu re) is applied on front wheel and rear wheel on the inner
side of turn. Moment directing towards the inner side of turn is generated. Understeer is prevented.
 Applying braking during a cornering on a slippery road, when understeer tendency is judged large, engine
output is controlled as well as brake force (brake fluid pressure) of four wheels. Understeer tendency
decreases.
TCS FUNCTION
TCS FUNCTION : System DescriptionINFOID:0000000006222573
 Wheel spin status of drive wheel is detected by wheel sensor of 4
wheels. Engine output and transmission shift status is controlled
so that slip rate of drive wheels is in appropriate level. When wheel
spin occurs on drive wheel, ABS ac tuator and electric unit (control
unit) perform brake force control of LH and RH drive wheels (apply
brake force by increasing brake fluid pressure of drive wheel) and
decrease engine torque by engine torque control. Wheel spin
amount decreases. Engine torque is controlled to appropriate
level.
 TCS function can be switched to non-operational status (OFF) by
operating VDC OFF switch. In this case, VDC OFF indicator lamp
turns ON.
 TCS function is not operate when 4WD mode is “4L”. (Models with
4WD system)
 VDC warning lamp blinking while TCS function is in operation and indicates to the driver that the function is in operation.
 Slight vibrations are felt on the brake pedal and the operation noises occur, when TCS function operates. This is not a malfunc-
tion because it is caused by TCS function that is normally oper-
ated.
 CONSULT-III can be used to diagnose the system diagnosis.
 Fail-safe function is adopted. W hen a malfunction occurs in TCS
function, the control is suspended for VDC function, TCS function,
hill start assist function and brake limited slip differential (BLSD)
function. The vehicle status becomes the same as models without VDC function, TCS function, hill start
assist function and brake limited slip differential (B LSD) function. However, ABS function and EBD function
are operated normally. Refer to BRC-25, "
Fail-safe".
SYSTEM DIAGRAM
NOTE:
JPFIC0137GB
JPFIC0138GB
JPFIC0139GB
Revision: 2010 May2011 QX56

BRC-32
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
Transfer control unit is appli
ed to models with 4WD system.
INPUT SIGNAL AND OUTPUT SIGNAL
Major signal transmission between each unit via communication lines is shown in the following table.
*1: Communication line between yaw rate/side/decal G s ensor and ABS actuator and electric unit (control unit)
*2: Models with 4WD system
ABS FUNCTION
JPFIC0183GB
Component Signal description
Yaw rate/side/decel G sensor Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via com-
munication line
*1.
 Yaw rate signal
 Side G sensor signal
 Decel G sensor signal
ECM Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Accelerator pedal position signal
 Engine speed signal
Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 Target throttle position signal
TCM Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Shift position signal
Transfer control unit
*2Mainly transmits the following si gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Current 4WD mode signal
Steering angle sensor Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Steering angle sensor signal
Combination meter Mainly receives
the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 VDC warning lamp signal
 VDC OFF indicator lamp
Revision: 2010 May2011 QX56

BRC-34
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
Transfer control unit is appli
ed to models with 4WD system.
INPUT SIGNAL AND OUTPUT SIGNAL
Major signal transmission between each unit via communication lines is shown in the following table.
*1: Communication line between yaw rate/side/decal G s ensor and ABS actuator and electric unit (control unit)
*2: Models with 4WD system
EBD FUNCTION
EBD FUNCTION : System DescriptionINFOID:0000000006222575
 By preventing rear wheel slip increase through rear wheel brake force (brake fluid pressure) control that is
electronically controlled when slight skip on front and r ear wheels are detected during braking, stability dur-
ing braking is improved.
JPFIC0184GB
Component Signal description
Yaw rate/side/decel G sensor Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via com-
munication line
*1.
 Yaw rate signal
 Side G sensor signal
 Decel G sensor signal
Transfer control unit
*2Mainly transmits the following si gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Current 4WD mode signal
Combination meter Mainly receives
the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 ABS warning lamp signal
Revision: 2010 May2011 QX56

BRC-38
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
 Brake limited slip differential (BLSD) function operates
while VDC function is in non-operational status (OFF)
by VDC OFF switch.
 VDC warning lamp blinking while brake limited slip di fferential (BLSD) function is in operation and indicates
to the driver that the function is in operation.
 Slight vibrations are felt on the brake pedal and the operation noises occur, when brake limited slip differen-
tial (BLSD) function operates. This is not a malfunction because it is caused by brake limited slip differential
(BLSD) function that is normally operated.
 Fail-safe function is adopted. When a malfunction occurs in brake limited slip differential (BLSD) function,
the control is suspended for VDC function, TCS function, hi ll start assist function and brake limited slip differ-
ential (BLSD) function. The vehicle status becomes the same as models without VDC function, TCS func-
tion, hill start assist function and brake limited slip di fferential (BLSD) function. However, ABS function and
EBD function are operated normally. Refer to BRC-25, "
Fail-safe".
SYSTEM DIAGRAM
NOTE:
Transfer control unit is applied to models with 4WD system.
INPUT SIGNAL AND OUTPUT SIGNAL
Major signal transmission between each unit via communication lines is shown in the following table.
JPFIC0183GB
Component Signal description
Yaw rate/side/decel G sensor Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via com-
munication line
*1.
 Yaw rate signal
 Side G sensor signal
 Decel G sensor signal
ECM Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Accelerator pedal position signal
 Engine speed signal
Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 Target throttle position signal
TCM Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Shift position signal
Revision: 2010 May2011 QX56

SYSTEMBRC-39
< SYSTEM DESCRIPTION > [WITH VDC]
C
D
E
G H
I
J
K L
M A
B
BRC
N
O P
*1: Communication line between yaw rate/side/decal G s ensor and ABS actuator and electric unit (control unit)
*2: Models with 4WD system
Transfer control unit*2Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN
communication.
 Current 4WD mode signal
Steering angle sensor Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN
communication.
 Steering angle sensor signal
Combination meter Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 VDC warning lamp signal
 VDC OFF indicator lamp
Component Signal description
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM [ABS ACTUATOR AND ELECTRIC UNIT (CONTROL
UNIT)]
BRC-41
< SYSTEM DESCRIPTION > [WITH VDC]
C
D
E
G H
I
J
K L
M A
B
BRC
N
O P
FR RH IN SOL
(On/Off) ×Operation status of front
RH wheel ABS IN valve is dis-
played.
FR RH OUT SOL
(On/Off) ×Operation status of front
RH wheel ABS OUT valve is dis-
played.
FR LH IN SOL
(On/Off) ×
Operation status of front LH wheel ABS IN valve is dis-
played.
FR LH OUT SOL
(On/Off) ×Operation status of front LH wheel ABS OUT valve is dis-
played.
RR RH IN SOL
(On/Off) ×
Operation status of rear RH wh eel ABS IN valve is displayed
RR RH OUT SOL
(On/Off) ×
Operation status of rear RH wheel ABS OUT valve is dis-
played.
RR LH IN SOL
(On/Off) ×Operation status of rear LH
wheel ABS IN valve is dis-
played.
RR LH OUT SOL
(On/Off) ×Operation status of rear LH
wheel ABS OUT valve is dis-
played.
EBD WARN LAMP
(On/Off) Brake warning lamp ON/OFF status is displayed.
(Note 1)
STOP LAMP SW
(On/Off)××
Stop lamp switch signal input status is displayed.
MOTOR RELAY
(On/Off) ×
ABS motor and motor relay status is displayed.
ACTUATOR RLY
(On/Off) ×
ABS actuator relay status is displayed.
ABS WARN LAMP
(On/Off) ×
ABS warning lamp ON/OFF status is displayed.
(Note 1)
OFF LAMP
(On/Off) ×
VDC OFF indicator lamp ON/OFF status is displayed.(Note 1)
OFF SW
(On/Off) ××
VDC OFF switch signal input status is displayed.
SLIP/VDC LAMP
(On/Off) ×
VDC warning lamp ON/OFF status is displayed.
(Note 1)
BATTERY VOLT
(V) ××Voltage supplied to ABS actuator and electric unit (control
unit) is displayed.
GEAR ××Current gear position judged from current gear position sig-
nal is displayed.
ENGINE SPEED
(tr/min) ××
Engine speed status is displayed.
YAW RATE SEN
(d/s) ××
Yaw rate detected by yaw rate sensor is displayed.
R POSI SIG
(On/Off) R range signal input status judged from R range signal is
displayed.
4WD MODE MON
(Note 2)
(AUTO/LOCK/##) ××
4WD control status is displayed.
N POSI SIG
(On/Off) N range signal input status judged from N range signal is
displayed.
CV1
(On/Off) Cut valve 1 operation status is displayed.
CV2
(On/Off) Cut valve 2 operation status is displayed.
SV1
(On/Off) Suction valve 1 operation status is displayed.
Item (Unit)
Monitor item selection
Note
INPUT SIGNALS MAIN ITEMS
Revision: 2010 May2011 QX56