2011 INFINITI QX56 brake

EC-48
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
AUTOMATIC SPEED CONTROL DEVI CE (ASCD) : System Diagram
INFOID:0000000006217715
AUTOMATIC SPEED CONTROL DEVICE (ASCD) : System DescriptionINFOID:0000000006217716
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM via the CAN communication line
BASIC ASCD SYSTEM
 Automatic Speed Control Device (ASCD) allows a dr iver to keep vehicle at predetermined constant speed
without depressing accelerator pedal. Driver can be set the vehicle speed in the set speed range.
 ECM controls throttle angle of electric th rottle control actuator to regulate engine speed.
 Operation status of ASCD is indicated in combination meter.
 If any malfunction occurs in the ASCD system, it automatically deactivates the ASCD control.
Refer to EC-49, "
AUTMATIC SPEED CONTROL DEVICE (A SCD) : Switch Name and Function" for ASCD
operating instructions.
CAUTION:
Always drive vehicle in a safe manner according to traffic conditions and obey all traffic laws.
CAN COMMUNICATION
CAN COMMUNICATION : System DescriptionINFOID:0000000006217718
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication s peed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CA N communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
Refer to LAN-28, "
CAN COMMUNICATION SYSTEM : CAN Communication Signal Chart", about CAN com-
munication for detail.
JPBIA3272GB
Sensor Input signal to ECM ECM function Actuator
ASCD steering switch ASCD steering switch operation
ASCD vehicle speed control Electric throttle control ac-
tuator
 Combination meter
ASCD brake switch
Brake pedal operation
Sto p l am p s w it ch
TCM Park/neutral position signal
Output shaft revolution signal*
Combination meter Vehicle speed signal*
Revision: 2010 May2011 QX56

OPERATIONEC-49
< SYSTEM DESCRIPTION > [VK56VD]
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OPERATION
AUTMATIC SPEED CONTROL DEVICE (ASCD)
AUTMATIC SPEED CONTROL DEVICE (A
SCD) : Switch Name and Function
INFOID:0000000006217719
SWITCHES AND INDICATORS
SET SPEED RANGE
ASCD system can be set the following vehicle speed.
SWITCH OPERATION
CANCEL CONDITION
 When any of following conditions exist, the cruise operation is canceled.
- CANCEL switch is pressed
- ASCD MAIN switch pressed (Set speed is cleared)
- More than two switches at ASCD steering switch ar e pressed at the same time (Set speed is cleared)
- Brake pedal is depressed
- Selector lever position is changed to N, P or R
- Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed
- TCS system is operated
 When the ECM detects any of the following conditions , the ECM cancels the cruise operation and informs
the driver by blinking CRUISE indicator lamp.
1. CRUISE indicator lamp 2. CANCEL switch 3. ASCD MAIN switch
4. SET/COAST switch 5. RESUME/ACCELERATE switch
A. On the combination meter B. On the steering wheel
JPBIA3226ZZ
Minimum speed (Approx.) Maximum speed (Approx.)
40 km/h (25 MPH) 143 km/h (88 MPH)
Item Function
CANCEL switch Cancels the cruise control driving.
RESUME/ACCELERATE switch  Resumes the set speed.
 Increases speed incrementally during cruise control driving.
SET/COAST switch  Sets desired cruise speed.
 Decreases speed incrementally during cruise control driving.
ASCD MAIN switch Master switch to activate the ASCD system.
(CRUISE indicator lamp is turn
ed ON when ASCD system is ON.)
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-67
< SYSTEM DESCRIPTION > [VK56VD]
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OLOAD SIGNAL ON/OFF
 Indicates [ON/OFF] condition from the electrical
load signal.
ON: Rear window defogger switch is ON and/or
lighting switch is in 2nd position.
OFF: Both rear window defogger switch and light-
ing switch are OFF.
IGNITION SW ON/OFF  Indicates [ON/OFF] condition from ignition switch
signal.
HEATER FAN SW ON/OFF  Indicates [ON/OFF] condition from the blower fan
ON signal.
BRAKE SW ON/OFF  Indicates [ON/OFF] condition from the stop lamp
switch signal.
IGN TIMING BTDC  Indicates the ignition timing computed by ECM ac-
cording to the input signals.  When the engine is stopped,
a certain value is indicated.
COMBUSTION —  These items are displayed but are not applicable to
this model.
CAL/LD VALUE %  “Calculated load value” indicates the value of the
current air flow divided by peak air flow.
MASS AIRFLOW g/s  Indicates the mass air flow computed by ECM ac-
cording to the signal voltage of the mass air flow
sensor.
PURG VOL C/V %  Indicates the EVAP canister purge volume control
solenoid valve control value computed by the ECM
according to the input signals.
 The opening becomes larger as the value increas-
es.
INT/V SOL (B1)
% The control value of the intake valve timing control
solenoid valve (determined by ECM according to
the input signals) is indicated.
 The advance angle becomes larger as the value increases.
INT/V SOL (B2)
AIR COND RLY ON/OFF
 The air conditioner relay control condition (deter-
mined by ECM according to the input signals) is in-
dicated.
VENT CONT/V ON/OFF  The control condition of the EVAP canister vent
control valve (determined by ECM according to the
input signals) is indicated.
ON: Closed
OFF: Open
THRTL RELAY ON/OFF  Indicates the throttle co
ntrol motor relay control
condition determined by the ECM according to the
input signals.
A/F S1 HTR (B1)
% Air fuel ratio (A/F) sensor 1 heater control value
computed by ECM according to the input signals.
 The current flow to the heater becomes larger as the value increases.
A/F S1 HTR (B2)
HO2S2 HTR (B1)
ON/OFF Indicates [ON/OFF] condition of heated oxygen
sensor 2 heater determined by ECM according to
the input signals.
HO2S2 HTR (B2)
ALT DUTY SIG ON/OFF  The control condition of the power generation volt-
age variable control (determined by ECM accord-
ing to the input signals) is indicated.
ON: Power generation voltage variable control is
active.
OFF: Power generation voltage variable control is
inactive.
I/P PULLY SPD rpm  Indicates the engine speed computed from the in-
put speed sensor signal.
Monitored item Unit Description Remarks
Revision: 2010 May2011 QX56

EC-68
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
VEHICLE SPEED km/h or mph The vehicle speed computed from the vehicle
speed signal sent from TCM is displayed.
IDL A/V LEARN YET/CMPLT  Displays the condition of Idle Air Volume Learning
YET: Idle air volume learning has not been per-
formed yet.
CMPLT: Idle air volume learning has already been
performed successfully.
TRVL AFTER MIL km or mile  Distance traveled while MIL is activated.
SNOW MODE SW ON/OFF  Indicates [ON/OFF] condition from the snow mode
switch signal.
ENG OIL TEMP °C or °F  The engine oil temperature (determined by the sig-
nal voltage of the engine oil temperature sensor) is
displayed.
MAIN SW ON/OFF  Indicates [ON/OFF] condition from MAIN switch
signal.
CANCEL SW ON/OFF  Indicates [ON/OFF] condition from CANCEL
switch signal.
RESUME/ACC SW ON/OFF  Indicates [ON/OFF] condition from RESUME/AC-
CELERATE switch signal.
SET SW ON/OFF  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  Indicates [ON/OFF] condition of stop lamp switch
signal.
DIST SW ON/OFF  Indicates [ON/OFF] condition from DISTANCE
switch signal.
CRUISE LAMP ON/OFF  Indicates [ON/OFF] condition of CRUISE indicator
determined by the ECM according to the input sig-
nals.
AC EVA TEMP °C or °F  Indicates A/C evaporator temperature sent from A/
C auto amp.
AC EVA TARGET °C or °F  Indicates target A/C evaporator temperature sent
from A/C auto amp.
FAN DUTY %  Indicates a command value for cooling fan. The
value is calculated by ECM based on input signals.
ALT DUTY %  Indicates the duty ratio of the power generation
command value. The ratio is calculated by ECM
based on the battery current sensor signal.
BAT CUR SEN mV  The signal voltage of battery current sensor is dis-
played.
A/F ADJ-B1
— Indicates the correction of a factor stored in ECM.
The factor is calculated from the difference be-
tween the target air-fuel ratio stored in ECM and
the air-fuel ratio calculated from A/F sensor 1 sig-
nal.
A/F ADJ-B2
P/N POSI SW ON/OFF
 Indicates [ON/OFF] condition from the park/neutral
position (PNP) signal.
INT/A TEMP SE °C or °F  The intake air temperature (determined by the sig-
nal voltage of the intake air temperature sensor) is
indicated.
AC PRESS SEN V  The signal voltage from the refrigerant pressure
sensor is displayed.
FUEL PRES SEN MPa  Indicates the fuel rail pressure computed by ECM
according to the input signals
Monitored item Unit Description Remarks
Revision: 2010 May2011 QX56

ECM
EC-73
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TP SEN 1-B1
 Ignition switch: ON
(Engine stopped)
 Selector lever: D position Accelerator pedal: Fully released More than 0.36 V
Accelerator pedal: Fully depressed Less than 4.75 V
TP SEN 2-B1*
1 Ignition switch: ON (Engine stopped)
 Selector lever: D position Accelerator pedal: Fully released More than 0.36 V
Accelerator pedal: Fully depressed Less than 4.75 V
FUEL T/TMP SE  Ignition switch: ON Indicates fuel tank tempera-
ture
EVAP SYS PRES  Ignition switch: ON Approx. 1.8 - 4.8 V
FUEL LEVEL SE  Ignition switch: ON Depending on fuel level of
fuel tank
START SIGNAL  Ignition switch: ON → START → ON OFF → ON → OFF
CLSD THL POS  Ignition switch: ON
(Engine stopped) Accelerator pedal: Fully released ON
Accelerator pedal: Slightly depressed OFF
AIR COND SIG  Engine: After warming up, idle
the engine Air conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates.)
ON
PW/ST SIGNAL  Engine: After warming up, idle
the engine Steering wheel: Not being turned OFF
Steering wheel: Being turned ON
LOAD SIGNAL  Ignition switch: ON Rear window defogger switch: ON
and/or
Lighting switch: 2nd position
ON
Rear window defogger switch and lighting
switch: OFF OFF
IGNITION SW  Ignition switch: ON → OFF → ON ON → OFF → ON
HEATER FAN SW  Engine: After warming up, idle
the engine Heater fan switch: ON ON
Heater fan switch: OFF OFF
BRAKE SW  Ignition switch: ON Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
IGN TIMING  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle 1 - 4
°BTDC
2,000 rpm 25 - 45 °BTDC
COMBUSTION — These items are displayed
but are not applicable to this
model.
CAL/LD VALUE  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle 5 - 35%
2,500 rpm 5 - 35%
MASS AIRFLOW  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle 2.0 - 6.0 g/s
2,500 rpm 7.0 - 20.0 g/s
PURG VOL C/V  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle
(Accelerator pedal: Not depressed even
slightly, after engine starting.)
0%
2,000 rpm 5%
INT/V SOL (B1)  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle 0 - 2%
2,000 rpm Approx. 0 - 50%
Monitor Item Condition Values/Status
Revision: 2010 May2011 QX56

EC-74
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ECM
INT/V SOL (B2) Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle 0 - 2%
2,000 rpm Approx. 0 - 50%
AIR COND RLY  Engine: After warming up, idle
the engine A/C switch: OFF OFF
A/C switch: ON
(Compressor operates)
ON
VENT CONT/V  Ignition switch: ON OFF
THRTL RELAY  Ignition switch: ON ON
A/F S1 HTR (B1)  Engine: After warming up, idle the engine
(More than 140 seconds after starting engine) 4 - 100%
A/F S1 HTR (B2)  Engine: After warming up, idle the engine
(More than 140 seconds after starting engine) 4 - 100%
HO2S2 HTR (B1)  Engine speed: Below 3,600 rpm after the following conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at
idle for 1 minute under no load ON
 Engine speed: Above 3,600 rpm OFF
HO2S2 HTR (B2)  Engine speed: Below 3,600 rpm after the following conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at
idle for 1 minute under no load ON
 Engine speed: Above 3,600 rpm OFF
ALT DUTY SIG  Power generation voltage variable control: Operating ON
 Power generation voltage variable control: Not operating OFF
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-III value with the speedometer in-
dication. Almost the same speed as
the speedometer indication
IDL A/V LEARN  Engine: Running Idle air volume learning has not been per-
formed yet.
YET
Idle air volume learning has already been
performed successfully. CMPLT
TRVL AFTER MIL  Ignition switch: ON Vehicle has traveled after MIL has illumi-
nated.0 - 65,535 km
(0 - 40,7
23 miles)
SNOW MODE SW  Ignition switch: ON Snow mode switch: ON ON
Snow mode switch: OFF OFF
ENG OIL TEMP  Engine: After warming up More than 70 °C (158 °F)
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
BRAKE SW1
(ASCD/ICC brake
switch)  Ignition switch: ON
Brake pedal: Fully released ON
Brake pedal: Slightly depressed OFF
Monitor Item Condition Values/Status
Revision: 2010 May2011 QX56

ECM
EC-75
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BRAKE SW2
(Stop lamp switch)
 Ignition switch: ON Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
DIST SW  Ignition switch: ON DISTANCE switch: Pressed ON
DISTANCE switch: Released OFF
CRUISE LAMP  Ignition switch: ON MAIN switch: Pressed at the 1st time
→
at the 2nd time ON
→ OFF
AC EVA TEMP  Engine: Running Indicates A/C evaporator
temperature sent from“uni-
fied meter and A/C amp.”.
AC EVA TARGET  Engine: Running Indicates target A/C evapo-
rator temperature sentfrom
“unified meter and A/C
amp.”.
FAN DUTY  Engine: Running 0 - 100%
ALT DUTY  Engine: Idle 0 - 80%
BAT CUR SEN  Engine speed: Idle
 Battery: Fully charged*
2
 Selector lever: P or N position
 A/C switch: OFF
No load Approx. 2,600 - 3,500 mV
A/F ADJ-B1  Engine: Running −0.330 - 0.330
A/F ADJ-B2  Engine: Running −0.330 - 0.330
P/N POSI SW  Ignition switch: ON Selector lever: P or N ON
Selector lever: Except above position OFF
INT/A TEMP SE  Ignition switch: ON Indicates intake air temper-
ature
AC PRESS SEN  Engine: Idle
 Both A/C switch and blower fan switch: ON (Compressor operates) 1.0 - 4.0 V
FUEL PRES SEN  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle Approx. 2.74 Mpa
2,000 rpm Approx. 3.0 Mpa
FUEL INJ B1  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle Approx. 1.4 msec
2,000 rpm Approx. 1.0 msec
FUEL INJ B2  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle Approx. 1.4 msec
2,000 rpm Approx. 1.0 msec
INT/V TIM (B1)  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle
−5 - 5 °CA
2,000 rpm Approx. 0 - 30 °CA
INT/V TIM (B2)  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle
−5 - 5 °CA
2,000 rpm Approx. 0 - 30 °CA
MAP SENSOR  Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle Approx. 1.0 V
2,000 rpm Approx. 1.35 V
EVAP LEAK DIAG  Ignition switch: ON Indicates the condition of
EVAP leak diagnosis.
Monitor Item Condition Values/Status
Revision: 2010 May2011 QX56

EC-92
< ECU DIAGNOSIS INFORMATION >[VK56VD]
ECM
142
(R/W) 175
(B) Fuel pump control module
(FPCM) check
Input[When cranking engine] 0 V
[Engine is running]
 Warm-up condition
 Idle speed
9 V
143
(L/Y) 150
(R) EVAP control system pressure
sensor
Input [Ignition switch: ON] 1.8 - 4.8 V
144
(O/B) 150
(R) Refrigerant pressure sensor Input [Engine is running]
 Warm-up condition
 Both A/C switch and blower fan mo-
tor switch: ON (Compressor oper-
ates) 1.0 - 4.0 V
146 (L) — CAN communication line — — —
147
(G/Y) 175
(B) ASCD/ICC brake switch Input [Ignition switch: ON]
 Brake pedal: Slightly depressed
0 V
[Ignition switch: ON]
 Brake pedal: Fully released BATTERY VOLTAGE
(11 - 14 V)
150 (R) —Sensor ground
(Refrigerant pressure sensor/
Battery current sensor/EVAP
control system pressure sensor) —— —
151 (P) — CAN communication line — — —
156 (L) 175
(B) Power supply
for ECM (Back-
up) Input [Ignition switch: OFF] BATTERY VOLTAGE
(11 - 14 V)
158
(W/B) 175
(B) Stop lamp switch Input [Ignition switch: OFF]
 Brake pedal: Fully released
0 V
[Ignition switch: OFF]
 Brake pedal: Slightly depressed BATTERY VOLTAGE
(11 - 14 V)
161 (R/W) — ENG communication line — — —
163
(L/G) 175
(B) ECM relay (Self shut-off) Output [Engine is running]
[Ignition switch: OFF]
 A few seconds after turning ignition
switch OFF 0 - 1.5 V
[Ignition switch: OFF]
 More than a few seconds after turn- ing ignition switch OFF BATTERY VOLTAGE
(11 - 14 V)
165
(GR/ R) —
NOTE:
Not used —— —
166 (W) — ENG communication line — — —
Te r m i n a l N o .
(Wire color) Description
ConditionVa l u e
(Approx.)
+ – Signal name Input/
Output
Revision: 2010 May2011 QX56