2011 INFINITI QX56 Factory Service Manual

oil viscosity door lock wheel bolt torque battery replacement lumbar support service schedule

Page 545 of 5598

INFINITI QX56 2011 Factory Service Manual
BRC-28
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
*1: Models with 4WD System
*2: Models with Advanced Driver Assistance System
Protection FunctionINFOID:0000000006228185
The VDC warning lamp, ABS warnin

BRC-28
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
*1: Models with 4WD System
*2: Models with Advanced Driver Assistance System
Protection FunctionINFOID:0000000006228185
The VDC warning lamp, ABS warning lamp and brake warning lamp turns ON and DTC “C118E” may be
detected in self-diagnosis result of “ABS” when the br
ake pedal is excessively operated, such as air bleeding.
This is not a system malfunction because this occurs due to the temporary decrease in accumulator fluid pres-
sure. The system returns to normal condition when the accu mulator fluid pressure reaches the specified pres-
sure with the ignition switch ON and the VDC warning lamp, ABS warning lamp, and brake warning lamp turn
OFF. After these steps, erase self-diagnos is results for “ABS” with CONSULT-III.
NOTE:
D T C “ C 1111 ” i s d e t e c t e d i n s e l f - d i agnosis results of “ABS” when the a ccumulator system has a malfunction.
VDC FUNCTION
VDC FUNCTION : System DescriptionINFOID:0000000006222572
Side slip or tail slip may occur while driving on a slippery road or intending an urgent evasive driving. VDC
function detects side slip status using each sensor when side slip or tail slip is about to occur and improves
vehicle stability by brake control and engine output control during driving.
In addition to ABS function, EBD function and TCS functi on, target side slip amount is calculated according
to steering operation amount from steering angle sensor and brake operation amount from pressure sensor.
By comparing this information with vehicle side slip amount that is calculated from information from yaw rate/
C118EWhen performing excessive brake pedal operation with the vehicle stopped. [When
accumulator fluid pressure reaches 11.43 MPa (114 bar, 116.6 kg/cm2, 1657 psi) af-
ter reaching 17.3 MPa (173 bar, 176.5 kg/cm2, 2509 psi.] The following functions are sus-
pended.
VDC function
TCS function
ABS function
EBD function
hill start assist function
Brake limited slip differential
(BLSD) function
U1000 When CAN communication signal is not continuously received for 2 seconds or
more. The following functions are sus-
pended.
VDC function
TCS function
ABS function
hill start assist function
Brake limited slip differential
(BLSD) function
DTC Malfunction detected condition Fail-safe condition
DTC
VDC warning lamp
ABS warning lamp
Brake warning lamp
Condition Description protection function
C118E ON When temporary decrease in accumulator fluid pres-
sure.
NOTE:
System is not malfunction. The following functions are suspended
temporarily
VDC function
TCS function
ABS function
EBD function
hill start assist function
Brake limited slip differential (BLSD)
function
Revision: 2010 May2011 QX56

Page 546 of 5598

INFINITI QX56 2011 Factory Service Manual
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

Page 547 of 5598

INFINITI QX56 2011 Factory Service Manual
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

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

Page 548 of 5598

INFINITI QX56 2011 Factory Service Manual
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 o

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

Page 549 of 5598

INFINITI QX56 2011 Factory Service Manual
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 communicatio

Page 550 of 5598

INFINITI QX56 2011 Factory Service Manual
SYSTEMBRC-33
< SYSTEM DESCRIPTION > [WITH VDC]
C
D
E
G H
I
J
K L
M A
B
BRC
N
O P
ABS FUNCTION : System DescriptionINFOID:0000000006222574
By preventing wheel lock through brake force (brake flui d

SYSTEMBRC-33
< SYSTEM DESCRIPTION > [WITH VDC]
C
D
E
G H
I
J
K L
M A
B
BRC
N
O P
ABS FUNCTION : System DescriptionINFOID:0000000006222574
By preventing wheel lock through brake force (brake flui d pressure) control that is electronically controlled by
detecting wheel speed during braking, stability during em ergency braking is improved so that obstacles can
be easily bypassed by steering operation.
During braking, control units calculates wheel speed and pseudo-vehicle speed, and transmits pressure
increase, hold or decrease signals to actuator portion according to wheel slip status.
The following effects are obtained by preventing wheel lock during
braking.
- Vehicle tail slip is prevented during braking when driving straight.
- Understeer and oversteer tendencie s are moderated during brak-
ing driving on a corner.
- Obstacles may be easily bypassed by steering operation during braking.
Slight vibrations are felt on the brake pedal and the operation noises occur, when ABS function oper ates. This is not a malfunc-
tion because it is caused by ABS function that is normally oper-
ated.
CONSULT-III can be used to diagnose the system diagnosis.
Fail-safe function is adopted. When a malfunction occurs in ABS 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, ABS func tion, hill start assist function
and brake limited slip differential (BLSD) function. However, EBD
function is operated normally. Refer to BRC-25, "
Fail-safe".
NOTE:
ABS has the characteristic as described here, but it is not the device that helps reckless driving.
To stop vehicle efficiently, ABS does not operate and ordinary brake operates at low speed [approx. 5 to 10 km/h (3.1 to 6.2
MPH) or less, but differs subject to road conditions).
Self-diagnosis is performed immediately after when engine starts and when vehicle initially is driven [by vehi-
cle speed approx. 15 km/h (9.3 MPH)]. Motor sounds are generated during self-diagnosis. In addition, brake
pedal may be felt heavy when depressing brake pedal lightly. These symptoms are not malfunctions.
SYSTEM DIAGRAM
NOTE:
JPFIC0140GB
Revision: 2010 May2011 QX56

Page 551 of 5598

INFINITI QX56 2011 Factory Service Manual
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 communicatio

Page 552 of 5598

INFINITI QX56 2011 Factory Service Manual
SYSTEMBRC-35
< SYSTEM DESCRIPTION > [WITH VDC]
C
D
E
G H
I
J
K L
M A
B
BRC
N
O P
EBD function is expanded and developed from conventi onal ABS function and corrects rear wheel brake
force to approp

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