2008 INFINITI QX56 cruise control

CCS
NORMAL OPERATING CONDITIONCCS-67
< SYMPTOM DIAGNOSIS >
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• The sensor detection distance is limited if the vehicle-to-vehicle distance is close. The vehicle distance may not maintain properly
because the motorcycle (A) driving on the lane edge is not
detected or detecting the vehicle ahead (cutting in the own vehicle)
delays.
• The sensor dirt is detected automat ically. But it is not perfect. Dirt
is not judged despite the sensor is dirt. Dirt is not detected if snow
or ice is on the sensor.
Keeping the vehicle-to-vehicle distance is difficult. Drive the vehi-
cle safely. Always clean the sensor.
Intelligent Cruise Control is released automatically if dirt is
detected.
• The vehicle ahead may not be detected temporarily, the vehicle or object on the neighboring lane may be
detected or the warning buzzer may sound according to the road shape (curve and narrow road) and the
own vehicle condition (steering, driving lane position, accident , malfunction etc.).
The vehicle ahead is not detected temporarily. The vehicle approaches too close.
PRECAUTIONS FOR CONVENTIONAL (F IXED SPEED) CRUISE CONTROL MODE
• Conventional cruise control mode does neither control the brake nor activate the warning.
Drive the vehicle safely. Keep a safe distance between vehicles by decreasing the vehicle speed according
to the driving condition etc.
• Never use the conventional cruise control mode in the following conditions.
- A well-trafficed road, and a tight turn. It may cause any accident because the driving does not fit to the road condition.
- A slippery road (e.g., freezing, or snowy road) The vehicle may lose the control by wheelspin.
- A steep downhill The engine brake does not activate effectively on a steep downhill. The preset vehicle speed may exceed.
JSOIA0050ZZ
Revision: March 2010 2008 QX56

P1827 CLUTCH PRESSURE SWITCHDLN-71
< COMPONENT DIAGNOSIS > [ATX14B]
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YES >> GO TO 5.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRAN SFER CONTROL UNIT AND CLUTCH PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the transfer terminal cord assembly harness con-
nector.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 34 and transfer terminal cord assembly har-
ness connector F56 terminal 7
Also check harness for short to ground and short to power.
Are inspection results normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
3.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are inspection results normal?
YES >> GO TO 4.
NO >> Check transfer control unit pin terminals fo r damage or loose connection with the harness connec-
tor. If any items are damaged, repair or replace damaged parts.
4.CHECK CLUTCH PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to DLN-16, "
Component Parts Location".
3. Push and release clutch pressure switch and check continuity
between terminal 7 and ground.
Are inspection results normal?
YES >> GO TO 5.
NO >> Replace clutch pressure switch.
5.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Are inspection results normal?
YES >> GO TO 6.
NO >> Replace transfer control unit. Refer to DLN-128, "
Removal and Installation".
6.CRUISE TEST
Perform cruise test. Refer to DLN-7, "
Preliminary Check".
Are inspection results normal?
YES >> Inspection End.
NO >> Perform the applicable trouble diagnosis.
Component InspectionINFOID:0000000001737162
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to DLN-16, "
Component Parts Location".
Continuity should exist.
SDIA2747E
Terminal
Condition Continuity
7 -
Ground Push clutch pressure switch
Yes
Release clutch pressure switch No
WDIA0171E
Revision: March 2010 2008 QX56

P1828 LINE PRESSURE SWITCHDLN-75
< COMPONENT DIAGNOSIS > [ATX14B]
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Are inspection results normal?
YES >> GO TO 6.
NO >> Replace transfer control unit. Refer to DLN-128, "
Removal and Installation".
6.CRUISE TEST
Perform cruise test. Refer to DLN-7, "
Preliminary Check".
Are inspection results normal?
YES >> Inspection End.
NO >> Perform the applicable trouble diagnosis.
Component InspectionINFOID:0000000001737166
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove line pressure switch. Refer to DLN-16, "
Component Parts Location".
3. Push and release line pressure switch and check continuity between terminal 1 and ground.
4. If the inspection results are abnormal, replace the line pressure switch.
Terminal Condition Continuity
1 - Ground Push line pressure switch
Yes
Release line pressure switch No
WDIA0172E
Revision: March 2010 2008 QX56

AUTOMATIC SPEED CONTROL DEVICE (ASCD)EC-33
< FUNCTION DIAGNOSIS > [VK56DE]
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AUTOMATIC SPEED CONTROL DEVICE (ASCD)
System DescriptionINFOID:0000000001351238
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line
BASIC ASCD SYSTEM
Refer to Owner's Manual for ASCD operating instructions.
Automatic Speed Control Device (ASCD) allows a driver to keep vehicle at predetermined constant speed
without depressing accelerator pedal. Driver can set
vehicle speed in advance between approximately 40 km/
h (25 MPH) and 144 km/h (89 MPH).
ECM controls throttle angle of electric thro ttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE i ndicator and SET indicator in combination meter. If any
malfunction occurs in ASCD system, it automatically deactivates control.
NOTE:
Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws.
SET OPERATION
Press MAIN switch. (The CRUISE indicato r in combination meter illuminates.)
When vehicle speed reaches a desired speed between approximately 40 km/h (25 MPH) and 144 km/h (89
MPH), press SET/COAST switch. (Then SET indicator in combination meter illuminates.)
ACCELERATE OPERATION
If the RESUME/ACCELERATE switch is pressed during cr uise control driving, increase the vehicle speed until
the switch is released or vehicle speed reac hes maximum speed controlled by the system.
And then ASCD will keep the new set speed.
CANCEL OPERATION
When any of following conditions exis t, cruise operation will be canceled.
• CANCEL switch is pressed
• More than 2 switches at ASCD steer ing switch are pressed at the same time (Set speed will be cleared)
• Brake pedal is depressed
• Selector lever is changed to N, P, R position
• Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed
• VDC system is operated
When the ECM detects any of the following conditions, the ECM will cancel the cruise operation and inform
the driver by blinking indicator lamp.
• Engine coolant temperature is slightly higher than the normal operating temperature, CRUISE lamp may
blink slowly.
When the engine coolant temperature decreases to t he normal operating temperature, CRUISE lamp will
stop blinking and the cruise operation will be able to work by pressing SET/COAST switch or RESUME/
ACCELERATE switch.
• Malfunction for some self-diagnoses regarding ASCD control: SET lamp will blink quickly.
If MAIN switch is turned to OFF during ASCD is activated, all of ASCD operations will be canceled and vehicle
speed memory will be erased.
COAST OPERATION
When the SET/COAST switch is pressed during cruise control driving, decrease vehicle set speed until the
switch is released. And then ASCD will keep the new set speed.
RESUME OPERATION
Sensor Input signal to ECM ECM functionActuator
ASCD brake switch Brake pedal operation
ASCD vehicle speed controlElectric throttle control
actuator
Stop lamp switch
Brake pedal operation
ASCD steering switch ASCD steering switch operation
Wheel sensor Vehicle speed*
TCM Powertrain revolution*
Gear position
Revision: March 2010
2008 QX56

EC-70
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
A/F S1 HTR (B1)
[%]• A/F sensor 1 heater control value com-
puted by ECM according to the input sig-
nals.
• The current flow to the heater becomes larger as the value increases.
A/F S1 HTR (B2)
[%]
AC PRESS SEN [V]
ו The signal voltage from the refrigerant
pressure sensor is displayed.
VHCL SPEED SE
[km/h] or [mph] ו The vehicle speed computed from the
vehicle speed signal sent from combina-
tion meter is displayed.
SET VHCL SPD
[km/h] or [mph] ×
• The preset vehicle speed is displayed.
MAIN SW
[ON/OFF] ו Indicates [ON/OFF] condition from MAIN
switch signal.
CANCEL SW
[ON/OFF] ×
• Indicates [ON/OFF] condition from CAN-
CEL switch signal.
RESUME/ACC SW
[ON/OFF] ו Indicates [ON/OFF] condition from RE-
SUME/ACCELERATE switch signal.
SET SW
[ON/OFF] ו Indicates [ON/OFF] condition from SET/
COAST switch signal.
BRAKE SW1
[ON/OFF] ×
• Indicates [ON/OFF] condition from
ASCD brake switch signal.
BRAKE SW2
[ON/OFF] ו Indicates [ON/OFF] condition of stop
lamp switch signal.
DIST SW
[ON/OFF] • Indicates [ON/OFF] condition from DIS-
TANCE switch signal.
VHCL SPD CUT
[NON/CUT] • Indicates the vehicle cruise condition.
NON: Vehicle speed is maintained at the
ASCD set speed.
CUT: Vehicle speed increased to exces-
sively high compared with the ASCD set
speed, and ASCD operation is cut off.
LO SPEED CUT
[NON/CUT] • Indicates the vehicle cruise condition.
NON: Vehicle speed is maintained at the
ASCD set speed.
CUT: Vehicle speed decreased to exces-
sively low compared with the ASCD set
speed, and ASCD operation is cut off.
AT O D M O N I T O R
[ON/OFF] • Indicates [ON/OFF] condition of A/T O/D
according to the input signal from the
TCM.
AT O D C A N C E L
[ON/OFF] • Indicates [ON/OFF] condition of A/T O/D
cancel signal sent from the TCM.
CRUISE LAMP
[ON/OFF] • Indicates [ON/OFF] condition of CRUISE
lamp determined by the ECM according
to the input signals.
SET LAMP
[ON/OFF] • Indicates [ON/OFF] condition of SET
lamp determined by the ECM according
to the input signals.
ALT DUTY [%] • Indicates the duty ratio of the power gen-
eration command value. The ratio is cal-
culated by ECM based on the battery
current sensor signal.
BAT CUR SEN [mV] • The signal voltage of battery current sen-
sor is displayed.
Monitored item
[Unit] ECM IN-
PUT SIG-
NALS MAIN
SIGNALS Description
Remarks
Revision: March 2010 2008 QX56

EC-394
< COMPONENT DIAGNOSIS >[VK56DE]
ASCD INDICATOR
ASCD INDICATOR
Component DescriptionINFOID:0000000001365868
ASCD indicator lamp illuminates to indicate ASCD
operation status. Lamp has two indicators, CRUISE and
SET, and is integrated in combination meter.
CRUISE indicator illuminates when MAIN switch on ASCD st eering switch is turned ON to indicate that ASCD
system is ready for operation.
SET indicator illuminates when following conditions are met.
• CRUISE indicator is illuminated.
• SET/COAST switch on ASCD steering switch is turned ON while vehicle speed is within the range of ASCD setting.
SET indicator remains lit during ASCD control.
Refer to EC-33
for the ASCD function.
Diagnosis ProcedureINFOID:0000000001365871
1.CHECK OVERALL FUNCTION
Check ASCD indicator under the following conditions.
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
2.CHECK DTC
Check that DTC U1000 or U1001 is not displayed.
OK or NG
OK >> GO TO 3.
NG >> Perform trouble diagnosis for DTC U1000, U1001. Refer to EC-87
.
3.CHECK COMBINATION METER FUNCTION
Refer to MWI-5
.
OK or NG
OK >> GO TO 4.
NG >> Go to MWI-5
.
4.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
>> INSPECTION END
ASCD INDICATOR CONDITIONSPECIFICATION
CRUISE LAMP • Ignition switch: ON • MAIN switch: Pressed at the 1st
time → at the 2nd time ON
→ OFF
SET LAMP • MAIN switch: ON
• When vehicle speed is between
40 km/h (25 MPH) and 144 km/h
(89 MPH) • ASCD: Operating
ON
• ASCD: Not operating OFF
Revision: March 2010 2008 QX56

EC-428
< ECU DIAGNOSIS >[VK56DE]
ECM
*1: Accelerator pedal position sensor 2 signal and throttle position sensor 2 signal are converted by ECM internally. Thus, the
y differ
from ECM terminals voltage signal.
*2: Before measuring the terminal voltage, confirm the battery is fully charged. Refer to PG-73
.
I/P PULLY SPD • Vehicle speed: More than 20 km/h (12 MPH)
Almost the same speed as the
tachometer indication
VEHICLE SPEED • Turn drive wheels and compare CONSULT-IIl value with the speedometer
indication. Almost the same speed as the
speedometer indication
TRVL AFTER MIL • Ignition switch: ON Vehicle has traveled after MIL has
turned ON.0 - 65,535 km
(0 - 40,723 mile)
A/F S1 HTR (B1)
A/F S1 HTR (B2) • Engine: After warming up, idle the engine
4 - 100%
AC PRESS SEN • Engine: Idle
• Both A/C switch and blower fan switch: ON (Compressor operates.)
1.0 - 4.0V
VHCL SPEED SE • Turn drive wheels and compare CONSULT-IIl value with the speedometer
indication. Almost the same speed as the
speedometer indication
SET VHCL SPD • Engine: Running ASCD: Operating.The preset vehicle speed is dis-
played.
MAIN SW • Ignition switch: ON MAIN switch: Pressed
ON
MAIN switch: Released OFF
CANCEL SW • Ignition switch: ON CANCEL switch: Pressed
ON
CANCEL switch: Released OFF
RESUME/ACC SW • Ignition switch: ON RESUME/ACCELERATE switch:
Pressed
ON
RESUME/ACCELERATE switch: Re-
leased OFF
SET SW • Ignition switch: ON SET/COAST switch: Pressed
ON
SET/COAST switch: Released OFF
DIST SW • Ignition switch: ON DISTANCE switch: Pressed
ON
DISTANCE switch: Released OFF
BRAKE SW1 • Ignition switch: ON Brake pedal: Fully released
ON
Brake pedal: Slightly depressed OFF
BRAKE SW2 • Ignition switch: ON Brake pedal: Fully released
OFF
Brake pedal: Slightly depressed ON
CRUISE LAMP • Ignition switch: ON MAIN switch: Pressed at the 1st time
→ at the 2nd timeON
→ OFF
SET LAMP • MAIN switch: ON
• Vehicle speed: Between 40 km/h
(25 MPH) and 144 km/h (89
MPH) ASCD: Operating
ON
ASCD: Not operating OFF
ALT DUTY • Engine: Idle 0 - 80%
BAT CUR SEN • Engine speed: Idle
• Battery: Fully charged*
2
• Selector lever: P or N
• Air conditioner switch: OFF
•No load Approx. 2,600 - 3,500mV
ALT DUTY SIG • Power generation voltage variable control: Operating
ON
• Power generation voltage variable control: Not operating OFF
MONITOR ITEM
CONDITION SPECIFICATION
Revision: March 2010 2008 QX56

CONSULT-III CHECKING SYSTEMGI-47
< BASIC INSPECTION >
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x : Applicable
*1: With intelligent cruise control
*2: With 4-wheel drive
*3: With security card installed
CONSULT-III Data Link Connector (DLC) CircuitINFOID:0000000001555031
INSPECTION PROCEDURE
If the CONSULT-III cannot diagnose the sys tem properly, check the following items.
NOTE:
The CAN and DDL2 circuits from DLC pins 6, 7 and 14 may be connected to more than one system. A short in
any circuit connected to a control unit in one system may affect CONSULT-III access to other systems.
Passenger AirbagDisplays the STATUS (readiness) of the front passen-
ger air bag. ----x-----------
AV COMM monitor The condition of AV communication can be indicated.------------x---
Configuration Sets control module parame
ters to match vehicle op-
tions. ------x---------
PIN read
*3This mode shows the BCM-specific 5-digit code. ------x---------
Control unit initial-
ization
*3All registered ignition key IDs in NATS components
can be initialized and new IDs can be registered. ------x---------
Diagnostic test
mode Function
ENGINE
TRANSMISSION
ICC
*1
ABS
AIR BAG
IPDM E/R BCM
METER/M&A
INTELLIGENT KEY
AUTO DRIVE POS.
REARVIEW CAMERA AIR LEVELIZER MULTI AV
ALL MODE AWD/4WD
*2
HVAC
SONAR
Symptom Check item
CONSULT-III cannot access
any system. • CONSULT-III DLC power supply circuit (Terminal 8) and ground circuit (Terminal 4)
CONSULT-III cannot access in-
dividual system. (Other sys-
tems can be accessed.) • Power supply and ground circuit for the control unit of the system (For detailed circuit, refer to wiring
diagram for each system.)
• Open or short circuit between the system and CONSULT-III DLC (For detailed circuit, refer to wiring diagram for each system.)
• Open or short circuit CAN communication line. Refer to LAN-14, "
Trouble Diagnosis Flow Chart".
Revision: March 2010 2008 QX56