2011 INFINITI QX56 brake sensor

SBC-6
< SYSTEM DESCRIPTION >
COMPONENT PARTS
Component Description
INFOID:0000000006237876
A. View with instrument driver lower cov- er removed B. Combination switch C. View with center pillar lower garnish
removed (driver side)
D. View with center pillar lower garnish re- moved (passenger side)
Component Function
ABS actuator and electric unit (control unit) ABS operation signal is rece
ived from ABS actuator and el ectric unit (control unit)
via CAN communication.
ADAS control unit Intelligent brake assistance operation signal is received from ADAS control unit
via CAN communication.
Air bag diagnosis sensor unit  Detects a collision and supplies power supply for deployment to air bag module
and pre-tensioner seat belt.
 Performs the deploy judgement of passenger air bag based on the information from Occupant Detection System control unit
BCM Ignition ON signal, sleep/wake up signal, and door switch signal are received
from BCM via CAN communication.
Brake pedal stroke sensor  It changes voltage according to brake pedal depressed amount and sends the
signal to pre-crash seat belt control unit.
 There are 2 signals (brake pedal stroke sensor 1 and 2) sent from the brake
pedal stroke sensor. Pre-crash seat belt control unit judges the stroke amount
and the speed of the brake pedal according to the voltage of the signal sent by
each side.
Combination meter  Transmits vehicle speed signal to pre-crash seat belt control unit (driver side).
 Turns the seat belt warning lamp ON when the seat belt is unfastened.
Occupant detection system control unit Judges the passenger seat condition based on the information from occupant de-
tection unit.
Pre-crush seat belt control unit (driver side)  Total control of pre-crash seat belt system is operated according to transmit sig-
nal.
 Driver seat belt retractor integrates pre-crash seat belt control unit (driver side), driver seat belt motor, and tension reducer.
 Seat belt motor operates each operation of pull, return, and hold.
Pre-crush seat belt control unit (passenger side)  Control of passenger pre-crash seat belt is operated according to transmit sig-
nal.
 Passenger seat belt retractor integrates pre-crash seat belt control unit (driver seat), driver seat belt motor, and tension reducer.
 Seat belt motor operates each operation of pull, return, and hold.
Seat belt buckle switch (driver side)  Fastening or not fastening of seat belt is judged. This judgment is used for con-
trol of driver pre-crash seat belt system.
 Seat belt warning lamp on combination meter turns ON when seat belt is not fastened while ignition switch is ON.
 The seat belt buckle switch is installed in the seat belt buckle.
Seat belt buckle switch (passenger side)  Fastening or not fastening of seat belt is judged. This judgment is used to con-
trol passenger pre-crash seat belt system.
 The seat belt buckle switch is installed in the seat belt buckle.
Steering angle sensor Steering angle sensor signal, steering angle speed signal, steering angle sensor
neutral position adjustment completion signal, and steering angle sensor mal-
function signal are received via CAN communication.
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (PRE-CRASH SEAT BELT)SBC-11
< SYSTEM DESCRIPTION >
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DIAGNOSIS SYSTEM (P RE-CRASH SEAT BELT)
CONSULT-III FunctionINFOID:0000000006237882
Diagnosis for pre-crash seat belt syst em can be performed using CONSULT-III.
APPLICATION ITEM
SELF-DIAGNOSIS RESULTS
Refer to SBC-16, "DTC Index".
CAUTION:
When malfunctions are detect ed in several systems, includin g CAN communication [U1000], trouble-
shoot CAN communication [U1000].
A malfunction of system may be disp layed when battery voltage is low (when 7 to 8 V is continued for
approximately 2 seconds) even though the system is not malfunctioning. Erase DTC memory and
never replace any parts after making sure that the syst em is normal, especially if the malfunctions are
displayed after replacing battery.
ERASING SELF-DIAGNOSIS RESULTS
 SELF-DIAGNOSIS RESULTS Current “SELF-DIAG RESULTS” are displayed. (If all suspect circuits have been repaired, “NO DTC” is dis-
played.)
DATA MONITOR
Part to be diagnosed Diagnosis Mode Function description
Pre-crash seat belt Self-diagnosis Results
 Displays data recorded when a malfunction is de-
tected.
 Erases DTC recorded in memory.
Data Monitor Displays input data for pre-crash seat belt control
unit in real time.
Work Support Changes the setting for each system function.
CAN DIAG SUPPORT MNTR Monitors communication status of CAN communi-
cation.
Ecu Identification Displays pre-crash seat belt control unit part num-
ber.
Monitor item Contents
BUCKLE SW RH Indicates [ON/OFF] condition of seat belt buckle switch (RH).
BUCKLE SW LH Indicates [ON/OFF] condition of seat belt buckle switch (LH).
VEHICLE DISTANCE Indicates [ON/OFF] condit ion of intelligent brake assist signal.
IGN SW Indicates [ON/OFF] condition of ignition switch.
FR DOOR SW RH Indicates [Close/Open] condition of front door switch (RH).
FR DOOR SW LH Indicates [Close/Open] condition of front door switch (LH).
ABS ACTIVATING Indicates [ON/OFF] co ndition of ABS operation signal.
VHCL SPEED Indicates [Km/h] vehicle speed signal.
BRK PEDAL SNSR1 Indicates [V] voltage of brake pedal stroke sensor 1 signal.
BRK PEDAL SNSR2 Indicates [V] voltage of brake pedal stroke sensor 2 signal.
STRG ANGLE Indicates [deg] steering angle signal.
STRG ANGLE SPEED Indicates [deg/s] steering angle speed signal.
INCLINATION JDMT Indicates [ON/OFF] condition of pre roll over signal.
PRE-TEN ACTIVTN Indicates [ON/OFF] condition of pre-tensioner operated signal.
HEAT PROTC RH Indicates [ON/OFF] condition of heat protection (RH).
HEAT PROTC LH Indicates [ON/OFF] condition of heat protection (LH).
Revision: 2010 May2011 QX56

SBC-14
< ECU DIAGNOSIS INFORMATION >
PRE-CRASH SEAT BELT CONTROL UNIT (DRIVER SIDE)
TERMINAL LAYOUT
PHYSICAL VALUES
Fail SafeINFOID:0000000006237884
 When a system malfunction is detected, deactivates a part of the system or all functions depending on the
malfunctioning part.
 When the malfunction condition recovers to the normal condition, the system returns to the normal opera-
tion.
JMHIA0711ZZ
Te r m i n a l N o .
(Wire color) Description
ConditionVa l u e
(Approx.)
+ – Signal name Input/
Output
1
(Y) Ground Power supply Input — Battery voltage
2
(G) Ground Brake pedal stroke sensor signal 1 Input Brake released
→ depressed 1 V - 4 V
4
(P) Ground CAN-L Input/
Output ——
6
(LG/R) Ground Seat belt buckle switch signal Input Seat belt is fastened 0 V
Seat belt is unfastened 5 V
8
(G) Ground Local Communication Line 2 Output IGN ON 5 V
9
(–) Ground Shield — — —
10
(R) Ground Brake pedal stroke sensor power circuit Output IGN ON 5 V
12
(B) Ground Brake pedal stroke sensor signal 2 Input Brake released
→ depressed 4 V - 1 V
14
(L) Ground CAN-H Input/
Output ——
16
(W) Ground Local Communication Line 1 Input/
Output ——
17
(W) Ground Brake pedal stroke sensor ground circuit — — 0 V
18
(B) Ground Ground — — 0 V
19
(W) Ground Motor drive circuit power supply Input — Battery voltage
20
(B) Ground Motor drive circuit ground — — 0 V
Revision: 2010 May2011 QX56

SBC-16
< ECU DIAGNOSIS INFORMATION >
PRE-CRASH SEAT BELT CONTROL UNIT (DRIVER SIDE)
DTC Index
INFOID:0000000006237885
DTC Trouble diagnosis name
(CONSULT-III display) DTC detection condition Reference
U0126 STRG ANG SEN SIG Steering angle sensor malfunction is received SBC-33
U0428 STRG ANGL CAL Steering angle sensor calibration incomplete signal is receivedSBC-34
U1000 CAN COMM CIRCUITPre-crash seat belt control unit cannot transmit and receive CAN
communication signal for 2 seconds or more SBC-35
B2451 SEAT BLT MTR DR CIRC Motor or control unit malfunction
 Seat belt motor circuit is open or shorted
SBC-36
B2452 SEAT BLT MTR AS CIRC Motor or control unit malfunction
 Seat belt motor circuit is open or shorted SBC-37
B2453 BR_STROKE_SEN_CIRC
 Brake pedal stroke sensor malfunction
 Brake pedal stroke sensor circuit is open or shorted SBC-38
B2454 SEAT BLT PWR DR CIRC Motor power su
pply circuit is open or shortedSBC-41
B2455 CONTROL UNIT DR Malfunction in pre-crash seat belt control unit SBC-42
B2456 SEAT BLT PWR AS CIRC Motor power supply circuit is open or shortedSBC-43
B2457 CONTROL UNIT AS Malfunction in pre-crash seat belt control unit SBC-44
B2458 LOCAL COMM Local communication line open or shortedSBC-45
B2461 VHCL SPEED SIGNAL Vehicle speed signal malfunction is received SBC-47
B2463 ROLLOVER SIGNAL Rollover signal malfunction is received SBC-48
B2466 DR/AS CONTROL UNIT Control unit is out of the vehicle specificationSBC-49
B2470 SYS HEAT PROTC DRDeactivation for cooling to prevent system heating due to continuous
operation SBC-50
B2471 SYS HEAT PROTC ASDeactivation for cooling to prevent system heating due to continuous
operation
SBC-51
Revision: 2010 May2011 QX56

SBC-38
< DTC/CIRCUIT DIAGNOSIS >
B2453 BR STROKE SEN CIRC
B2453 BR STROKE SEN CIRC
DTC LogicINFOID:0000000006237903
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON.
2. Check “Self-diagnostic result” with CONSULT-III.
Is DTC detected?
YES >> Refer to SBC-38, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006237904
1.CHECK PRE-CRASH SEAT BELT CONTROL UNIT INPUT SIGNAL
1. Turn ignition switch ON.
2. Select “BRK PEDAL SNSR1” and “BRK PEDAL SNSR2” in “DATA MONITOR” mode with CONSULT-III.
3. Check “BRK PEDAL SNSR1” and “BRK PEDAL SNSR2” indication under the following conditions.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
2.CHECK BRAKE PEDAL STROKE SENSOR POWER SUPPLY
1. Turn ignition switch OFF.
2. Disconnect brake pedal stroke sensor harness connector.
3. Check voltage between brake pedal stroke sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.CHECK BRAKE PEDAL STROKE SENSOR POWER SUPPLY CIRCUIT
1. Disconnect pre-crash seat belt contro l unit (driver side) harness connector.
2. Check continuity between pre-crash seat belt c ontrol unit (driver side) harness connector and brake pedal
stroke sensor harness connector.
DTC No. Self-diagnosis item DTC Detection Condition Possible causes
B2453 BR STROKE SEN CIRC Circuit of brake pedal stroke sensor out-
put is open or shorted  Harness or connectors
(The sensor circuit is open or shorted)
 Pre-crash seat belt co ntrol unit (driver side)
 Brake pedal stroke sensor
Monitor item Condition Voltage (V)
(Approx.)
BRK PEDAL SNSR1 Brake released → depressed 1
→ 4
BRK PEDAL SNSR2 4 → 1
Brake pedal stroke sensor
GroundVoltage (V)
(Approx.)
Connector Terminal
E 111 2 5
Pre-crash seat belt control unit (driver side) Brake pedal stroke sensor Continuity
Connector Terminal Connector Terminal
B9 10 E111 2 Existed
Revision: 2010 May2011 QX56

B2453 BR STROKE SEN CIRCSBC-39
< DTC/CIRCUIT DIAGNOSIS >
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3. Check continuity between pre-crash seat belt control unit (driver side) harness connector and ground.
Is the inspection result normal?
YES >> Replace pre-crash seat belt c ontrol unit (driver side). Refer to SB-6, "SEAT BELT RETRACTOR :
Removal and Installation".
NO >> Repair or replace harness or connector.
4.CHECK BRAKE PEDAL STROKE SENSOR CIRCUIT
1. Disconnect pre-crash seat belt control unit (driver side) harness connector.
2. Check continuity between pre-crash seat belt c ontrol unit (driver side) harness connector and brake pedal
stroke sensor harness connector.
3. Check continuity between pre-crash seat belt control unit harness connector (driver side) and ground.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace harness or connector.
5.CHECK BRAKE PEDAL STROKE SENSOR
Refer to SBC-39, "
Component Inspection".
Is the inspection result normal?
YES >> GO TO 6.
NO >> Replace brake pedal stroke sensor. Refer to SBC-63, "
Removal and Installation".
6.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000006237905
COMPONENT PARTS INSPECTION
1.CHECK BRAKE PEDAL STROKE SENSOR
1. Turn ignition switch OFF.
2. Disconnect brake pedal stroke sensor connector.
3. Check resistance between brake pedal stroke sensor terminal as per the following.
Pre-crash seat belt control unit (driver side)
GroundContinuity
Connector Terminal
B9 10 Not existed
Pre-crash seat belt control unit (driver side) Brake pedal stroke sensor Continuity
Connector Terminal Connector Terminal
B9 2
E 111 1
Existed
12 3
17 4
Pre-crash seat belt control unit (driver side) GroundContinuity
Connector Terminal
B9 2
Not existed
12
17
Revision: 2010 May2011 QX56

SBC-40
< DTC/CIRCUIT DIAGNOSIS >
B2453 BR STROKE SEN CIRC
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace brake pedal stroke sensor. Refer to SBC-63, "
Removal and Installation".
Brake pedal stroke sensor
ConditionResistance (k
Ω)
(Approx.)
Terminal
2 1
Brake released → depressed 1.0
→ 0.2
30.2 → 1.0
Revision: 2010 May2011 QX56

BRAKE PEDAL STROKE SENSORSBC-63
< REMOVAL AND INSTALLATION >
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REMOVAL AND INSTALLATION
BRAKE PEDAL STROKE SENSOR
Exploded ViewINFOID:0000000006237943
Removal and InstallationINFOID:0000000006237944
REMOVAL
1. Remove the instrument panel lower cover LH. Refer to IP-14, "Removal and Installation".
2. Disconnect the brake pedal stroke sensor connector.
3. Remove the screws (A).
4. Remove the brake pedal stroke sensor (1).
INSTALLATION
Install in the reverse order of removal.
1. Brake pedal stroke sensor
JMHIA0712ZZ
JMHIA0726ZZ
Revision: 2010 May2011 QX56