2011 INFINITI QX56 ECU

FRONT DISC BRAKEBR-35
< REMOVAL AND INSTALLATION >
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 Never deform the pad retainer when removing the pad retainers (2) from the torque member (1).
 Never damage the piston boot.
 Never drop the brake pads, shims and shim covers.
 Remember each position of the removed brake pads.
5. Perform inspection after removal. Refer to BR-36, "
BRAKE PAD
: Inspection".
INSTALLATION
WARNING:
Clean any dust from the brake caliper assembly an d brake pads with a vacuum dust collector. Never
blow with compressed air.
CAUTION:
 Never depress the brake pedal while removing th e brake pads because the piston may pop out.
 If the brake fluid or grease adheres to the brake cal iper assembly and disc rotor, quickly wipe it off.
1. Install the torque member if the pad retainers has been removed. CAUTION:
 Securely assemble the pad retainers (1) so that it will notbe lifted up from the torque member (2).
 Never deform the pad retainers.
2. Apply MOLYKOTE
® AS880N or silicone-based grease mating
faces (A and B) between the brake pad, shim and shim cover,
and install shim and shim cover to the brake pad.
CAUTION:
Always replace the shims and shim covers when replacing
the brake pad.
3. Install the brake pads to the torque member.
4. Install pad return springs (1). CAUTION:
Correctly insert the pad return spring into the pad return
spring hole on the brake pad.
5. Install cylinder body to torque member. CAUTION:
 Never damage the piston boot.
 When replacing brake pad with new one, check a brakefluid level in the reservoir tank because brake fluid
returns to reservoir tank when pressing piston in.
NOTE:
Use a disc brake piston tool to easily press piston.
6. Install lower sliding bolt and tighter it to the specified torque.
JPFIA0118ZZ
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Revision: 2010 May2011 QX56

FRONT DISC BRAKEBR-39
< REMOVAL AND INSTALLATION >
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2. Apply rubber grease to piston seals (1), and install them to cali- per.
CAUTION:
Never reuse piston seals.
3. Apply rubber grease to piston boots (1). Cover the piston (2) end with piston boot, and then install cylinder side lip on piston boots
securely into a groove on cylinder body.
CAUTION:
Never reuse piston boots.
4. Apply new brake fluid to pistons (1). Push piston into cylinder body by hand and push piston boots (2) piston-side lip into the
piston groove.
CAUTION:
Press the pistons evenly and var y the pressing point to pre-
vent cylinder inner wall from being rubbed.
5. Apply rubber grease to sliding pin boots, and install sliding pin boots to torque member.
6. Apply rubber grease to sliding pin, and install the cylinder body.
7. Install sliding pin bolts and tighten it to the specified torque. Refer to BR-34, "
BRAKE PAD : Exploded View".
BRAKE CALIPER ASSEMBLY : InspectionINFOID:0000000006222494
INSPECTION AFTER DISASSEMBLY
Check the following items and replace if necessary.
Cylinder Body
Check the cylinder inner wall for rust, wear, cracks or damage.
CAUTION:
Always clean with new brake fluid. Never clean wit h mineral oil such as gasoline and light oil.
Torque Member
Check the torque member for rust, wear, cracks or damage.
Pistons
Check the surface of the piston for rust, wear, cracks or damage.
CAUTION:
A piston sliding surface is plat ed. Never polish with sandpaper.
Sliding Pin and Sliding Pin Boot
Check the sliding pins and sliding pin boots for rust, wear, cracks or damage.
INSPECTION AFTER INSTALLATION
1. Check a drag of front disc brake. If any dr ag is found, follow the procedure described below.
2. Remove brake pads. Refer to BR-34, "
BRAKE PAD : Removal and Installation".
JPFIA0032ZZ
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Revision: 2010 May2011 QX56

BR-42
< REMOVAL AND INSTALLATION >
REAR DISC BRAKE
1. Install the torque member if the pad retainers has been removed.CAUTION:
 Securely assemble the pad retainers so that it wi ll not be lifted up from the torque member.
 Never deform the pad retainers.
2. Apply PCB (Poly Butyl Cuprysil) grease or silicone-based grease to the matching faces (A) between the brake pad and
shim, and install the shims to brake pads.
CAUTION:
Always replace the shims when replacing the brake pad.
3. Apply PCB (Poly Butyl Cuprysil) grease or silicone-based grease to the matching faces (B) between the brake pad and
torque member.
4. Install cylinder body to the torque member. CAUTION:
 Never damage the piston boot.
 When replacing brake pad with new one, check a brakefluid level in the reservoir tank because brake flui d returns to reservoir tank when pressing pis-
ton in.
NOTE:
Use a disc brake piston tool to easily press piston.
5. Install the upper sliding pin bolt and tighten it to the specified torque.
6. Depress the brake pedal several times to check that no drag feel is present for the front disc brake. Refer
to BR-42, "
BRAKE PAD : Inspection".
7. Install tires with power tool. Refer to WT-64, "
Exploded View".
BRAKE PAD : InspectionINFOID:0000000006222497
INSPECTION AFTER REMOVAL
 Replace the shims if rust is excessively attached.
 Eliminate rust on the pad retainers and the torque mem ber. Replace them if rust is excessively attached.
INSPECTION AFTER INSTALLATION
1. Check a drag of rear disc brake. If any drag is found, follow the procedure described below.
2. Remove brake pads. Refer to BR-41, "
BRAKE PAD : Removal and Installation".
3. Press the piston. Refer to BR-41, "
BRAKE PAD : Removal and Installation".
4. Install brake pads. Refer to BR-41, "
BRAKE PAD : Removal and Installation".
5. Depress the brake pedal several times.
6. Check a drag of rear disc brake again. If any drag is found, disassemble the caliper. Refer to BR-44,
"BRAKE CALIPER ASSEMBLY : Disassembly and Assembly".
7. Burnish contact surfaces brake pads and disc rotor after refinishing or replacing brake pads, or if a soft pedal occurs at very low mileage. Refer to BR-18, "
BRAKE PAD : Inspection and Adjustment".
BRAKE CALIPER ASSEMBLY
BRAKE CALIPER ASSEMBLY : Exploded ViewINFOID:0000000006222498
REMOVAL
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Revision: 2010 May2011 QX56

REAR DISC BRAKEBR-45
< REMOVAL AND INSTALLATION >
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5. Remove piston seal from cylinder body using suitable tool. CAUTION:
Be careful not to damage a cylinder inner wall.
6. Remove bleeder valve and cap.
7. Perform inspection after disassembly. Refer to BR-45, "
BRAKE
CALIPER ASSEMBLY : Inspection".
ASSEMBLY
1. Install bleeder valve and cap.
2. Apply rubber grease to piston seal (1), and install them to cylin-
der body.
CAUTION:
Never reuse piston seal.
3. Apply rubber grease to piston boot (1). Cover the piston (2) end with piston boot, and then install cylinder side lip on piston boot
securely into a groove on cylinder body.
CAUTION:
Never reuse piston boot.
4. Apply new brake fluid to piston (1). Push piston into cylinder body by hand and push piston boot (2) piston-side lip into the
piston groove.
CAUTION:
Press the piston evenly and var y the pressing point to pre-
vent cylinder inner wall from being rubbed.
5. Apply rubber grease to bushing, and install bushing to sliding pin bolt.
6. Apply rubber grease to sliding pin boots, and install sliding pin boots to torque member.
7. Apply rubber grease to sliding pin, and install the cylinder body.
8. Install sliding pin bolts and tighten it to the specified torque.Refer to BR-42, "
BRAKE CALIPER ASSEM-
BLY : Exploded View".
BRAKE CALIPER ASSEMBLY : InspectionINFOID:0000000006222501
INSPECTION AFTER DISASSEMBLY
Check the following items and replace if necessary.
Cylinder Body
Check the cylinder inner wall for rust, wear, cracks or damage.
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Revision: 2010 May2011 QX56

BRC-1
BRAKES
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SECTION BRC
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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-40
< SYSTEM DESCRIPTION >[WITH VDC]
DIAGNOSIS SYSTEM [
ABS ACTUATOR AND ELECTRIC UNIT (CONTROL
UNIT)]
DIAGNOSIS SYSTEM [ABS ACTUATOR AND ELECTRIC UNIT (CONTROL
UNIT)]
CONSULT-III FunctionINFOID:0000000006222578
APPLICATION ITEMS
CONSULT-III can display each diagnostic item using the diagnostic test modes as follows.
*: The following diagnosis information is erased by erasing.
DTC
 Freeze frame data (FFD)
ECU IDENTIFICATION
ABS actuator and electric unit (cont rol unit) part number can be read.
SELF DIAGNOSTIC RESULT
Refer to BRC-51, "DTC Index".
When “CRNT” is displayed on self-diagnosis result,
 The system is presently malfunctioning.
When “PAST” is displayed on self-diagnosis result, System malfunction in the past is detect ed, but the system is presently normal.
Freeze frame data (FFD)
DATA MONITOR
×: Applicable
Mode Function description
ECU identification Parts number of ABS actuator and electric unit (control unit) can be read.
Self Diagnostic Result Self-diagnostic results and freeze frame data can be read and erased quickly.
*
DATA MONITOR Input/Output data in the ABS actuator and electric unit (control unit) can be read.
ACTIVE TEST Diagnostic Test Mode in
which CONSULT-III drives some act uators apart from the ABS actuator and
electric unit (control unit) and also shifts some parameters in a specified range.
WORK SUPPORT Components can be quickly and accurately adjusted.
Item name Display item
IGN counter
(0 − 39) The number of times that ignition switch is tu
rned ON after the DTC is detected is displayed.
 When “0” is displayed: It indicates that the system is presently malfunctioning.
 When except “0” is displayed: It indicates that system malfunction in the past is detected, but the system is pres- ently normal.
NOTE:
Each time when ignition switch is turned OFF to ON, numerical number increases in 1 → 2 → 3...38 → 39. When
the operation number of times exceeds 39, the number do not increase and “39” is displayed until self-diagnosis
is erased.
Item (Unit) Monitor item selection
Note
INPUT SIGNALS MAIN ITEMS
FR LH SENSOR
[km/h (MPH)] ××Wheel speed calculated by front LH wheel sensor is dis-
played.
FR RH SENSOR
[km/h (MPH)] ××Wheel speed calculated by front RH wheel sensor is dis-
played.
RR LH SENSOR
[km/h (MPH)] ××
Wheel speed calculated by rear LH wheel sensor is dis-
played.
RR RH SENSOR
[km/h (MPH)] ××Wheel speed calculated by rear RH wheel sensor is dis-
played.
DECEL G-SEN
(G) ××
Decel G detected by decel G sensor is displayed.
Revision: 2010 May2011 QX56

ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)BRC-45
< ECU DIAGNOSIS INFORMATION > [WITH VDC]
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ECU DIAGNOSIS INFORMATION
ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
Reference ValueINFOID:0000000006222579
CONSULT-III DATA MONITOR STANDARD VALUE
Monitor item Condition Reference values in normal operation
FR LH SENSOR Vehicle stopped 0.00 km/h (MPH)
When driving
(Note 1)Nearly matches the speedometer dis-
play (within
±10%)
FR RH SENSOR Vehicle stopped 0.00 km/h (MPH)
When driving
(Note 1)Nearly matches the speedometer dis-
play (within
±10%)
RR LH SENSOR Vehicle stopped 0.00 km/h (MPH)
When driving
(Note 1)Nearly matches the speedometer dis-
play (within
±10%)
RR RH SENSOR Vehicle stopped 0.00 km/h (MPH)
When driving
(Note 1)Nearly matches the speedometer dis-
play (within
±10%)
DECEL G-SEN When stopped Approx. 0 G
During acceleration Positive value
During deceleration Negative value
FR RH IN SOL Active On
Inactive Off
FR RH OUT SOL Active On
Inactive Off
FR LH IN SOL Active On
Inactive Off
FR LH OUT SOL Active On
Inactive Off
RR RH IN SOL Active On
Inactive Off
RR RH OUT SOL Active On
Inactive Off
RR LH IN SOL Active On
Inactive Off
RR LH OUT SOL Active On
Inactive Off
EBD WARN LAMP When brake warning lamp is ON
(Note 2)On
When brake warning lamp is OFF
(Note 2)Off
STOP LAMP SW Brake pedal depressed On
Brake pedal not depressed Off
MOTOR RELAY Active On
Inactive Off
ACTUATOR RLY Active On
Inactive (in fail-safe mode) Off
Revision: 2010 May2011 QX56

BRC-46
< ECU DIAGNOSIS INFORMATION >[WITH VDC]
ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
ABS WARN LAMPWhen ABS warning lamp is ON
(Note 2)On
When ABS warning lamp is OFF
(Note 2)Off
OFF LAMP When VDC OFF indicator lamp is ON
(Note 2)On
When VDC OFF indicator lamp is OFF
(Note 2)Off
OFF SW VDC OFF switch ON On
VDC OFF switch OFF Off
SLIP/VDC LAMP When VDC warning lamp is ON or Blinking
(Note 2)On
When VDC warning lamp is OFF
(Note 2)Off
BATTERY VOLT Ignition switch ON 10 – 16 V
GEAR Driving 1 – 7
Depending on shift status
ENGINE SPEED Engine stopped 0 tr/min
Engine running Almost same reading as tachometer
YAW RATE SEN Vehicle stopped Approx. 0 d/s
Turning right Negative value
Turning left Positive value
R POSI SIG When selector lever is in the R position On
When selector lever is in the other position than R Off
4WD MODE MON
(Note 3)
When 4WD sift switch is AUTO position AUTO
When 4WD sift switch is 4H position LOCK
When 4WD sift switch is 4L position ##
N POSI SIG When selector lever is in the N position On
When selector lever is in the other position than N Off
CV1 Active On
Inactive Off
CV2 Active On
Inactive Off
SV1 Active On
Inactive Off
SV2 Active On
Inactive Off
STOP LAMP SW2 Brake pedal depressed On
Brake pedal not depressed Off
ACCEL POS SIG Never depress accelerator pedal
(with ignition switch ON)
0%
Depress accelerator pedal
(with ignition switch ON) 0 – 100%
SIDE G-SENSOR Vehicle stopped
Approx. 0 m/s
2
Right turn Negative value
Left turn Positive value
STR ANGLE SIG When driving straight 0
±2.5 °
When steering wheel is steered to LH by 90 °Approx. +90 °
When steering wheel is steered to RH by 90 °Approx. –90 °
Monitor item Condition Reference values in normal operation
Revision: 2010 May2011 QX56