2011 INFINITI QX56 stop start

BCS-58
< ECU DIAGNOSIS INFORMATION >
BCM
CONSULT display Fail-safeFreeze Frame Data
Vehicle Speed
Odo/Trip Meter
Vehicle Condition Intelligent Key warn-
ing lamp ON Reference
page
No DTC is detected.
further testing
may be required. ————
U1000: CAN COMM — — — BCS-70
U1010: CONTROL UNIT (CAN) — — —BCS-71
U0415: VEHICLE SPEED×— ×BCS-72
B2013: ID DISCORD BCM-S/L ××× SEC-69
B2014: CHAIN OF S/L-BCM××× SEC-70
B2192: ID DISCORD BCM-ECM×—— SEC-60
B2193: CHAIN OF BCM-ECM ×—— SEC-61
B2195: ANTI-SCANNING ×—— SEC-62
B2196: DONGLE NG ×—— SEC-63
B2198: NATS ANTENNA AMP ×—— SEC-65
B2555: STOP LAMP — ××SEC-73
B2556: PUSH-BTN IGN SW — ××SEC-76
B2557: VEHICLE SPEED ××× SEC-78
B2562: LOW VOLTAGE — ×—BCS-73
B2601: SHIFT POSITION ××× SEC-79
B2602: SHIFT POSITION××× SEC-82
B2603: SHIFT POSI STATUS××× SEC-85
B2604: PNP/CLUTCH SW××× SEC-89
B2605: PNP/CLUTCH SW××× SEC-91
B2608: STARTER RELAY××× SEC-93
B2609: S/L STATUS××× SEC-95
B260B: STEERING LOCK UNIT××× SEC-98
B260C: STEERING LOCK UNIT — ××SEC-99
B260D: STEERING LOCK UNIT ××× SEC-100
B260F: ENG STATE SIG LOST××× SEC-101
B2612: S/L STATUS××× SEC-102
B2614: BCM — ××PCS-56
B2615: BCM — ××PCS-59
B2616: BCM — ××PCS-61
B2618: BCM — ××PCS-63
B2619: BCM ××× SEC-105
B261A: PUSH-BTN IGN SW — ××PCS-64
B2621: INSIDE ANTENNA — ×—DLK-104
B2622: INSIDE ANTENNA — ×—DLK-106
B2623: INSIDE ANTENNA — ×—DLK-108
B2626: OUTSIDE ANTENNA — ×—DLK-110
B2627: OUTSIDE ANTENNA — ×—DLK-112
B2628: OUTSIDE ANTENNA — ×—DLK-114
B26E7: TPMS CAN COMM — — — BCS-74
Revision: 2010 May2011 QX56

HYDRAULIC BOOSTER ASSEMBLYBR-15
< PERIODIC MAINTENANCE >
C
DE
G H
I
J
K L
M A
B
BR
N
O P
HYDRAULIC BOOSTER ASSEMBLY
InspectionINFOID:0000000006222467
OPERATION CHECK
1. Turn the ignition switch OFF.
2. Depress the brake pedal 20 times or more. NOTE:
The pressure loss in the accumulator results in a large brake pedal stroke. In addition to this, the brake
pedal depression becomes lighter in initial stage.
3. Check that the fluid level in the reservoir tank is MAX line.
4. Position the selector lever in P range to release the parking brake.
5. Turn the ignition switch ON to check the time between motor activation and motor stop.
6. After the motor is stopped, check that the ABS warning lamp and the VDC warning lamp in the combina- tion meter are OFF when the engine is started.
7. Stop the engine (ignition switch OFF).
8. Turn the ignition switch ON and depress the brake pedal 4 to 5 times to check the time between motor activation and motor stop.
9. Turn the ignition switch OFF. Turn the ignition switch ON again. Check that the VDC warning lamp turns ON when the brake pedal is depressed 15 to 20 times.
10. Check that the VDC warning lamp turns ON when the brake pedal is depressed 15 to 20 times after the lapse of 120 seconds or more after the ignition switch is turned ON again.
11. Perform the self-diagnosis for “ABS” with CONSULT-III and erase self-diagnosis results.
FUNCTION CHECK
1. Turn the ignition switch OFF.
2. Depress the brake pedal 20 times or more.
NOTE:
The pressure loss in the accumulator results in a large brake pedal stroke. In addition to this, the brake
pedal depression becomes lighter in initial stage.
3. Turn the ignition switch ON with the brake pedal depr essed to check that the clearance between the brake
pedal and the dash lower panel decreases. Motor operating time : 18 seconds or less
Motor operating time : 2
− 11 seconds
Revision: 2010 May2011 QX56

BR-32
< REMOVAL AND INSTALLATION >
HYDRAULIC BOOSTER ASSEMBLY
 Apply new brake fluid to grommet of between reservoir tank and grommet and ABS actuator and electric unit
(control unit).
Inspection and AdjustmentINFOID:0000000006222486
ADJUSTMENT BEFORE INSTALLATION
Input Rod Length adjustment
1. Loosen the lock nut (1) and adjust the input rod (2) to the speci-
fied length (A).
2. Tighten the lock nut to the specified torque.
INSPECTION AFTER INSTALLATION
Operation Check
1. Turn the ignition switch OFF.
2. Depress the brake pedal 20 times or more. NOTE:
The pressure loss in the accumulator results in a large brake pedal stroke. In addition to this, the brake
pedal depression becomes lighter in initial stage.
3. Check that the fluid level in the reservoir tank is MAX line.
4. Position the selector lever in P range to release the parking brake.
5. Turn the ignition switch ON to check the time between motor activation and motor stop.
6. After the motor is stopped, check that the ABS warn ing lamp and the VDC warning lamp in the combina-
tion meter are OFF when the engine is started.
7. Stop the engine (ignition switch OFF).
8. Turn the ignition switch ON and depress the brake pedal 4 to 5 times to check the time between motor activation and motor stop.
9. Turn the ignition switch OFF. Turn the ignition swit ch ON again. Check that the VDC warning lamp turns
ON when the brake pedal is depressed 15 to 20 times.
10. Check that the VDC warning lamp turns ON when the brake pedal is depressed 15 to 20 times after the lapse of 120 seconds or more after the ignition switch is turned ON again.
11. Perform the self-diagnosis for “ABS” with CONSULT- III and erase all the stored self-diagnosis results.
Function Check
1. Turn the ignition switch OFF.
2. Depress the brake pedal 20 times or more.
NOTE:
The pressure loss in the accumulator results in a large brake pedal stroke. In addition to this, the brake
pedal depression becomes lighter in initial stage.
3. Turn the ignition switch ON with the brake pedal depr essed to check that the clearance between the brake
pedal and the dash lower panel decreases. A : Refer to
BR-47, "
Brake Booster".
JPFIA0728ZZ
Motor operating time : 18 seconds or less
Motor operating time : 2 − 11 seconds
Revision: 2010 May2011 QX56

BRC-1
BRAKES
C
DE
G H
I
J
K L
M
SECTION BRC
A
B
BRC
N
O P
CONTENTS
BRAKE CONTROL SYSTEM
WITH VDC
PRECAUTION ................ ...............................
5
PRECAUTIONS .............................................. .....5
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
5
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect .....................................
5
Precaution for Procedure without Cowl Top Cover ......6
Precaution for Brake System ....................................6
Precaution for Brake Control System ........................6
Precaution for Harness Repair ..................................7
PREPARATION ............................................9
PREPARATION .............................................. .....9
Commercial Service Tools .................................. ......9
SYSTEM DESCRIPTION .............................10
COMPONENT PARTS ................................... ....10
Component Parts Location .................................. ....10
Component Description ...........................................13
ABS Actuator and Electric Unit (Control Unit) .........14
Wheel Sensor and Sensor Rotor ............................14
Stop Lamp Switch ...................................................15
Steering Angle Sensor ............................................15
Yaw Rate/Side/Decel G sensor ...............................15
Brake Fluid Level Switch .........................................15
Parking Brake Switch ..............................................15
VDC OFF Switch .....................................................15
SYSTEM .............................................................16
System Description ............................................. ....16
Fail-safe ..................................................................25
Protection Function .................................................28
VDC FUNCTION .................................................... ....28
VDC FUNCTION : System Description ...................28
TCS FUNCTION ..................................................... ....31
TCS FUNCTION : System Description ....................31
ABS FUNCTION .................................................... ....32
ABS FUNCTION : System Description ....................33
EBD FUNCTION .................................................... ....34
EBD FUNCTION : System Description ....................34
HILL START ASSIST FUNCTION ......................... ....36
hill start assist FUNCTION : System Description ....36
BRAKE LIMITED SLIP DIFFERENTIAL (BLSD)
FUNCTION ............................................................. ....
37
BRAKE LIMITED SLIP DIFFERENTIAL (BLSD)
FUNCTION : System Description ............................
37
DIAGNOSIS SYSTEM [ABS ACTUATOR
AND ELECTRIC UNIT (CONTROL UNIT)] .......
40
CONSULT-III Function ............................................40
ECU DIAGNOSIS INFORMATION ..............45
ABS ACTUATOR AND ELECTRIC UNIT
(CONTROL UNIT) .............................................
45
Reference Value .................................................. ....45
Fail-safe ...................................................................47
Protection Function ..................................................50
DTC Inspection Priority Chart ..................................50
DTC Index ...............................................................51
WIRING DIAGRAM ......................................53
BRAKE CONTROL SYSTEM ...........................53
Wiring Diagram .................................................... ....53
BASIC INSPECTION ...................................60
DIAGNOSIS AND REPAIR WORK FLOW .......60
Work Flow ............................................................ ....60
Diagnostic Work Sheet ............................................61
Revision: 2010 May2011 QX56

BRC-6
< PRECAUTION >[WITH VDC]
PRECAUTIONS
5. When the repair work is completed, re-connect bot
h battery cables. With the brake pedal released, turn
the push-button ignition switch from ACC position to ON position, then to LOCK position. (The steering
wheel will lock when the push-button igniti on switch is turned to LOCK position.)
6. Perform self-diagnosis check of all control units using CONSULT-III.
Precaution for Procedure without Cowl Top CoverINFOID:0000000006228176
When performing the procedure after removing cowl top cover, cover
the lower end of windshield with urethane, etc.
Precaution for Brake SystemINFOID:0000000006222556
WARNING:
Clean any dust from the front brake and rear brake using a vacuum dust collector. Never blow by com-
pressed air.
 Brake fluid use refer to MA-10, "
Fluids and Lubricants".
 Never reuse drained brake fluid.
 Never spill or splash brake fluid on painted surfaces. Brake fluid may seriously damage paint. Wipe it off
immediately and wash with water if it gets on a painted surface.
 Always confirm the specified tightening torque when installing the brake pipes.
 After pressing the brake pedal more deeply or harder t han normal driving, such as air bleeding, check each
item of brake pedal. Adjust brake pedal if it is outside the standard value.
 Never use mineral oils such as gasoline or light oil to clean. They may damage rubber parts and cause
improper operation.
 Always loosen the brake tube flar e nut with a flare nut wrench.
 Tighten the brake tube flare nut to the specified torque with a crow-
foot (A) and torque wrench (B).
 Always connect the battery terminal when moving the vehicle.
 Turn the ignition switch OFF and disconnect the ABS actuator and
electric unit (control unit) harness connector or the battery negative
terminal before performing the work.
 Check that no brake fluid leakage is present after replacing the parts.
Precaution for Brak e Control SystemINFOID:0000000006222557
 Slight vibrations are felt on the brake pedal and the operation noises occur, when VDC function, TCS func-
tion, ABS function, EBD function, hill start assist function or brake limited slip differential (BLSD) function
operates. This is not a malfunction because it is caus ed by VDC function, TCS function, ABS function, EBD
function, hill start assist function or brake limited sl ip differential (BLSD) function that is normally operated.
 When starting engine or when starting vehicle just after starting engine, brake pedal may vibrate or motor
operating noise may be heard from engine compartment. This is normal condition.
 Brake stopping distance may become longer than models without ABS function depending on the road con-
ditions, when ABS function is operated on slippery r oad like rough road, gravel road or snowy road.
 When a malfunction is indicated, always collect info rmation from the customer about conditions of occur-
rence, estimate cause and perform operation. Check brake booster operation, brake fluid level and brake
fluid leakage, as well as electrical system.
 The optimum performance is achieved by control for V DC function, TCS function, ABS function, EBD func-
tion, hill start assist function or brake limited slip di fferential (BLSD) function when all of brakes, suspensions
PIIB3706J
JPFIA0001ZZ
Revision: 2010 May2011 QX56

PRECAUTIONSBRC-7
< PRECAUTION > [WITH VDC]
C
D
E
G H
I
J
K L
M A
B
BRC
N
O P
and tires installed on the vehicle are the specified si ze and parts. Brake performance and controllability may
be negatively affected when other parts than the specified are installed.
 Brake stopping distance may become longer and steering stability may be negatively affected, when tires in
different size and combination or other parts than the specified are used.
 When a radio (including wiring), antenna and antenna lead line are located near ABS actuator and electric
unit (control unit), a malfunction or improper operation ma y occur for the control of VDC function, TCS func-
tion, ABS function, EBD function, hill start assist func tion or brake limited slip differential (BLSD) function.
 When the following items are replaced by other parts than genuine parts or modified, ABS warning lamp, brake warning lamp and VDC warning lamp may turn ON, and the control may not operate normally for VDC
function, TCS function, ABS function, EB D function, hill start assist function or brake limited slip differential
(BLSD) function.
- Suspension component parts (shock absorber, spring, bushing and others)
- Tire and wheel (other than the specified size)
- Brake component parts (brake pad, disc rotor, brake caliper and others)
- Engine component parts (ECM, muffler and others)
- Body reinforcement component parts (rollover bar, tower bar and others)
 When suspension, tire and brake component parts are excessively worn or deteriorated and the vehicle is
driven, ABS warning lamp, brake warning lamp and VDC warning lamp may tu\
rn ON, and the control may
not operate normally for VDC function, TCS function, ABS function, EBD function, hill start assist function or
brake limited slip differential (BLSD) function.
 ABS warning lamp, brake warning lamp and VDC warning lamp may turn ON, when only front wheel or rear wheel is rotated using a free roller. This is not a ma lfunction, because it is caused by wheel speed difference
between wheel that is rotated and wheel that is not rota ted. In this case, perform self-diagnosis, check self-
diagnosis results, and erase memory.
 When power supply voltage is not normal, ABS warning lamp, brake warning lamp and VDC warning lamp
turn ON. ABS actuator and electric unit (control unit) st ops control for VDC function, TCS function, ABS func-
tion, EBD function, hill start assist function or brake limited slip differential (BLSD) function. Ordinary brake
operates. After power supply returns to normal, ABS warning lamp, brake warning lamp and VDC warning
lamp turn OFF. The control becomes operative for VD C function, TCS function, ABS function, EBD function,
hill start assist function or brake li mited slip differential (BLSD) function.
 VDC warning lamp may turn ON and VDC function or TCS function may not normally operate, when driving
on a special road the is extremely slanted (bank in a circ uit course). This is not a malfunction if the status
returns to normal for VDC function or TCS function after the engine is started again. In this case, perform
self-diagnosis, check self-diagnosis results, and erase memory.
 A malfunction in yaw rate/side/decel G sensor syste m may be detected when the vehicle sharply turns dur-
ing a spin turn, acceleration turn or drift driving while VDC function or TCS function are OFF (VDC OFF
switch is pressed and VDC OFF indicator lamp is in ON st atus). This is not a malfunction if the status returns
to normal for VDC function or TCS function after the engine is started again. In this case, perform self-diag-
nosis, check self-diagnosis results, and erase memory
Precaution for Harness RepairINFOID:0000000006222558
 Solder the repair part, and wrap it with tape. [Twisted wire fray must be 110 mm (4.33 in) or less.]
SKIB8766E
Revision: 2010 May2011 QX56

COMPONENT PARTSBRC-15
< SYSTEM DESCRIPTION > [WITH VDC]
C
D
E
G H
I
J
K L
M A
B
BRC
N
O P
 Downsize and weight reduction is aimed. IC for detection portion and magnet for sensor rotor are adopted.
 Power supply is supplied to detection portion so that magnetic field
line is read. Magnetic field that is detected is converted to current
signal.
 When sensor rotor rotates, magnetic field changes. Magnetic field
change is converted to current signals (rectangular wave) and is
transmitted to ABS actuator and electric unit (control unit). Change
of magnetic field is pr oportional to wheel speed.
Stop Lamp SwitchINFOID:0000000006222563
Detects the operation status of brake pedal and transmits converted electric signal to ABS actuator and elec-
tric unit (control unit).
Steering Angle SensorINFOID:0000000006222564
Detects the following information and transmits steering angle signal to ABS actuator and electric unit (control
unit) via CAN communication.
 Steering wheel rotation amount
 Steering wheel rotation angular velocity
 Steering wheel rotation direction
Yaw Rate/Side/Decel G sensorINFOID:0000000006222565
Calculates the following information that affects the v ehicle and transmits a signal to ABS actuator and electric
unit (control unit) via communication lines.
 Vehicle rotation angular velocity (yaw rate signal)
 Vehicle lateral acceleration (side G signal) / longitudinal acceleration (decel G signal)
Brake Fluid Level SwitchINFOID:0000000006222566
Detects the brake fluid level in reservoir tank and trans mits converted electric signal from ABS actuator and
electric unit (control unit), when brake fluid level is the specified level or less.
Parking Brake SwitchINFOID:0000000006222567
Detects the operation status of parking brake switch and transmits converted electric signal from combination
meter to ABS actuator and electric unit (control unit).
VDC OFF SwitchINFOID:0000000006222568
 VDC OFF switch is integrated in SNOW MODE / TOW MODE / VDC OFF switch assembly (2WD models) or
4WD switch assembly (4WD models).
 The operation of the VDC OFF switch enables the arbi trary switching of the VDC function between stop sta-
tus and standby status. The status of the function is indicated by the VDC OFF indicator lamp. (ON: Non-
operational status, OFF: Standby status)
- VDC function NOTE:
Brake limited slip differentia l (BLSD) control operates.
- TCS function
 VDC OFF indicator lamp turns OFF (standby status) when the engine is started again after it is stopped once while VDC OFF indicator lamp is ON (non-operational status).
JPFIC0131GB
Revision: 2010 May2011 QX56

BRC-26
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
ABS FUNCTION
ABS warning lamp and VDC warning lamp in combinati
on meter turn ON when a malfunction occurs in system
[ABS actuator and electric unit (control unit)]. The c ontrol is suspended for VDC function, TCS function, ABS
function, hill start assist function and brake limited sl ip differential (BLSD) function. The vehicle status
becomes the same as models without VDC function, TCS f unction, ABS function, hill start assist function and
brake limited slip differential (BLSD) function. However, EBD function is operated normally.
NOTE:
ABS self-diagnosis sound may be heard the same as in the normal condition, because self-diagnosis is per-
formed when ignition switch turns ON and when vehicle initially starts.
EBD FUNCTION
ABS warning lamp, brake warning lamp and VDC warning lamp in combination meter turn ON when a mal-
function occurs in system [ABS actuator and electric unit (control unit)]. The control is suspended for VDC
function, TCS function, ABS function, EBD function, hill start assist function and brake limited slip differential
(BLSD) function. The vehicle status becomes the sa me as models without VDC function, TCS function, ABS
function, EBD function, hill star t assist function and brake limited slip differential (BLSD) function.
DTC Malfunction detected condition Fail-safe condition
C1101 When an open circuit is detected in rear RH wheel sensor circuit.
The following functions are sus-
pended.
 VDC function
 TCS function
 ABS function
 EBD function (only when both 2 rear wheels are malfunctioning)
 hill start assist function
 Brake limited slip differential
(BLSD) function
C1102 When an open circuit is detected in rear LH wheel sensor circuit.
C1103 When an open circuit is detected in front RH wheel sensor circuit.
C1104 When an open circuit is detected in front LH wheel sensor circuit.
C1105
 When power supply voltage of rear RH wheel sensor is low.
 When distance between rear RH wheel sensor and rear RH wheel sensor rotor is
large.
 When installation of rear RH wheel sensor or rear RH wheel sensor rotor is not
normal.
C1106  When power supply voltage of rear LH wheel sensor is low.
 When distance between rear LH wheel sensor and rear LH wheel sensor rotor is
large.
 When installation of rear LH wheel sensor or rear LH wheel sensor rotor is not nor- mal.
C1107  When power supply voltage of front RH wheel sensor is low.
 When distance between front RH wheel sensor and front RH wheel sensor rotor
is large.
 When installation of front RH wheel sensor or front RH wheel sensor rotor is not normal.
C1108  When power supply voltage of front LH wheel sensor is low.
 When distance between front LH wheel sensor and front LH wheel sensor rotor is
large.
 When installation of front LH wheel sensor or front LH wheel sensor rotor is not normal.
C1109  When ignition voltage is 10 V or less.
 When ignition voltage is 16 V or more. The following functions are sus-
pended.
 VDC function
 TCS function
 ABS function
 EBD function
 hill start assist function
 Brake limited slip differential
(BLSD) function
C 1111
 When a malfunction is detected in motor or motor relay.
 When a low pressure malfunction is detected in accumulator.
 When a malfunction is detected in accumulator pressure sensor.
C 111 5 When difference in wheel speed between any wheel and others is detected during
the vehicle is driven, because of installation of other tires than specified. The following functions are sus-
pended.
 VDC function
 TCS function
 ABS function
 hill start assist function
 Brake limited slip differential
(BLSD) function
C 111 6
 When stop lamp switch signal is not input when brake pedal depress.
 When stop lamp switch signal is not input when stop lamp relay operates.
C 111 8
*1When a malfunction is detected in transfer control unit system.
Revision: 2010 May2011 QX56