2011 INFINITI QX56 engine

SYSTEMBRC-33
< SYSTEM DESCRIPTION > [WITH VDC]
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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

SYSTEMBRC-37
< SYSTEM DESCRIPTION > [WITH VDC]
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SYSTEM DIAGRAM
INPUT SIGNAL AND OUTPUT SIGNAL
Major signal transmission between each unit via communication lines is shown in the following table.
*: Communication line between yaw rate/side/decal G s ensor and ABS actuator and electric unit (control unit)
BRAKE LIMITED SLIP DIFFERENTIAL (BLSD) FUNCTION
BRAKE LIMITED SLIP DIFFERENTIAL (BLSD) FUNCTION : System Description
INFOID:0000000006222577
 LH and RH driving wheel spin is always monitored. If necessary, appropriate brake force is independently
applied to LH or RH driving wheel so that one-sided wheel spin is avoided and traction is maintained. Mainly
starting ability is improved.
JPFIC0145GB
Component Signal description
Yaw rate/side/decel G sensor Mainly transmits the following signals to ABS actuator and electric unit (control unit) via com-
munication line *.
 Yaw rate signal
 Side G sensor signal
 Decel G sensor signal
ECM Mainly transmits the following signals 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 signals to ABS actuator and electric unit (control unit) via CAN
communication.
 Shift position 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 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

DIAGNOSIS SYSTEM [ABS ACTUATOR AND ELECTRIC UNIT (CONTROL
UNIT)]
BRC-41
< SYSTEM DESCRIPTION > [WITH VDC]
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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

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

ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)BRC-51
< ECU DIAGNOSIS INFORMATION > [WITH VDC]
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*: Models with 4WD system
DTC IndexINFOID:0000000006222583
3  C1118 4WD SYSTEM
*
 C1130 ENGINE SIGNAL 1
 C1144 ST ANG SEN SIGNAL
4  C1109 BATTERY VOLTAGE [ABNORMAL]
 C 1111 P U M P M O T O R
C1140 ACTUATOR RLY
5  C1101 RR RH SENSOR-1
 C1102 RR LH SENSOR-1
 C1103 FR RH SENSOR-1
 C1104 FR LH SENSOR-1
 C1105 RR RH SENSOR-2
 C1106 RR LH SENSOR-2
 C1107 FR RH SENSOR-2
 C1108 FR LH SENSOR-2
 C1115 ABS SENSOR [ABNORMAL SIGNAL]
 C1116 STOP LAMP SW
 C1120 FR LH IN ABS SOL
 C1121 FR LH OUT ABS SOL
 C1122 FR RH IN ABS SOL
 C1123 FR RH OUT ABS SOL
 C1124 RRLH IN ABS SOL
 C1125 RR LH OUT ABS SOL
 C1126 RR RH IN ABS SOL
 C1127 RR RH OUT ABS SOL
 C1142 PRESS SEN CIRCUIT
 C1143 ST ANG SEN CIRCUIT
 C1145 YAW RATE SENSOR
 C1146 SIDE G-SEN CIRCUIT
 C1160 DECEL G SEN SET
C1164 CV 1
C1165 CV 2
 C1166 SV 1
 C1167 SV 2
6  C1155 BR FLUID LEVEL LOW
 C118E ACCUMULATOR PRESS
Priority Detected item (DTC)
DTC Items (CONSULT screen terms) Reference
C1101 RR RH SENSOR-1
BRC-68, "
DTC Logic"C1102 RR LH SENSOR-1
C1103 FR RH SENSOR-1
C1104 FR LH SENSOR-1
C1105 RR RH SENSOR-2BRC-70, "
DTC Logic"C1106 RR LH SENSOR-2
C1107 FR RH SENSOR-2
C1108 FR LH SENSOR-2
C1109 BATTERY VOLTAGE [ABNORMAL]BRC-72, "
DTC Logic"
C 1111 P U M P M O T O RBRC-75, "DTC Logic"
C1115 ABS SENSOR [ABNORMAL SIGNAL] BRC-77, "DTC Logic"
C1116 STOP LAMP SWBRC-79, "DTC Logic"
C 111 8*4WD SYSTEMBRC-87, "DTC Logic"
C1120 FR LH IN ABS SOL BRC-88, "DTC Logic"
Revision: 2010 May2011 QX56

BRC-52
< ECU DIAGNOSIS INFORMATION >[WITH VDC]
ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
*: Models with 4WD system
C1121 FR LH OUT ABS SOL
BRC-90, "DTC Logic"
C1122 FR RH IN ABS SOLBRC-88, "DTC Logic"
C1123 FR RH OUT ABS SOLBRC-90, "DTC Logic"
C1124 RRLH IN ABS SOLBRC-88, "DTC Logic"
C1125 RR LH OUT ABS SOLBRC-90, "DTC Logic"
C1126 RR RH IN ABS SOLBRC-88, "DTC Logic"
C1127 RR RH OUT ABS SOLBRC-90, "DTC Logic"
C1130 ENGINE SIGNAL 1BRC-92, "DTC Logic"
C1140 ACTUATOR RLYBRC-93, "DTC Logic"
C1142 PRESS SEN CIRCUITBRC-95, "DTC Logic"
C1143 ST ANG SEN CIRCUITBRC-97, "DTC Logic"
C1144 ST ANG SEN SIGNALBRC-99, "DTC Logic"
C1145 YAW RATE SENSOR
BRC-100, "DTC Logic"C1146 SIDE G-SEN CIRCUIT
C1155 BR FLUID LEVEL LOWBRC-103, "
DTC Logic"
C1160 DECEL G SEN SETBRC-105, "DTC Logic"
C1164 CV 1
BRC-106, "DTC Logic"C1165 CV 2
C1166 SV 1BRC-108, "
DTC Logic"C1167 SV 2
C1170 VARIANT CODING BRC-110, "
DTC Logic"
C118E ACCUMULATOR PRESS BRC-111, "DTC Logic"
U1000 CAN COMM CIRCUITBRC-112, "DTC Logic"
DTC Items (CONSULT screen terms) Reference
Revision: 2010 May2011 QX56

DIAGNOSIS AND REPAIR WORK FLOWBRC-61
< BASIC INSPECTION > [WITH VDC]
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YES >> GO TO 7.
NO >> Check harness and connectors based on the in formation obtained by interview. Refer to GI-40,
"Intermittent Incident".
7.FINAL CHECK
With CONSULT-III.
1. Check the reference value for “ABS”.
2. Recheck the symptom and check that the sympt om is not reproduced on the same conditions.
Is the symptom reproduced?
YES >> GO TO 3.
NO >> INSPECTION END
Diagnostic Work SheetINFOID:0000000006222586
Description
 In general, customers have their own criteria for a pr oblem. Therefore, it is important to understand the
symptom and status well enough by asking the customer about his/her concerns carefully. To systemize all
the information for the diagnosis, prepare the in terview sheet referring to the interview points.
 In some cases, multiple conditions that appear simultaneously may cause a DTC to be detected.
INTERVIEW SHEET SAMPLE
Interview sheet
Customer
name MR/MSRegistration
number
Initial year
registration
Vehicle type VIN
Storage date Engine Mileage km ( Mile)
Symptom †
Does not operate ( ) function
† Warning lamp for ( \
) turns ON.
† Noise † Vibration
† Other
( )
First occurrence † Recently † Other ( )
Frequency of occurrence † Always † Under a certain conditions of † Sometimes ( time(s)/day)
Climate con-
ditions †
Irrelevant
Weather † Fine † Cloud † Rain †Snow † Others ( )
Temperature † Hot †Warm † Cool † Cold † Temperature [Approx. °C ( °F)]
Relative humidity † High † Moderate † Low
Road conditions †
Urban area † Suburb area † Highway
† Mountainous road (uphill or downhill) †Rough road
Operating condition, etc. †
Irrelevant
† When engine starts † During idling
† During driving † During acceleration † At constant speed driving
† During deceleration
† During cornering (right curve or left curve)
† When steering wheel is steered (to right or to left)
Revision: 2010 May2011 QX56