Infiniti FX35 / FX45. Manual - part 319

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

EC-37

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AUTOMATIC SPEED CONTROL DEVICE (ASCD)

System Description

INFOID:0000000001325901

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 throttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE indicator 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 indicator 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.)

ACCELERATOR OPERATION

If the RESUME/ACCELERATE switch is pressed during cruise control driving, increase the vehicle speed until
the switch is released or vehicle speed reaches maximum speed controlled by the system.
And then ASCD will keep the new set speed.

CANCEL OPERATION

When any of following conditions exist, cruise operation will be canceled.
• CANCEL switch is pressed
• More than 2 switches at ASCD steering 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/TCS 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 the normal operating temperature, CRUISE lamp will
stop blinking and the cruise operation will be able to work by depressing 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 function

Actuator

ASCD brake switch

Brake pedal operation

ASCD vehicle speed control

Electric throttle control 
actuator

Stop lamp switch

Brake pedal operation

ASCD steering switch

ASCD steering switch operation

Park/neutral position (PNP) switch

Gear position

Wheel sensor.

Vehicle speed*

TCM

Powertrain revolution*

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AUTOMATIC SPEED CONTROL DEVICE (ASCD)

When the RESUME/ACCELERATE switch is pressed after cancel operation other than depressing MAIN
switch is performed, vehicle speed will return to last set speed. To resume vehicle set speed, vehicle condition
must meet following conditions.
• Brake pedal is released
• Selector lever is in other than P and N positions
• Vehicle speed is greater than 40 km/h (25 MPH) and less than 144 km/h (89 MPH)

Component Description

INFOID:0000000001325902

ASCD STEERING SWITCH

Refer to 

EC-459

.

ASCD BRAKE SWITCH

Refer to 

EC-474

 and 

EC-542

.

STOP LAMP SWITCH

Refer to 

EC-474

, 

EC-486

 and 

EC-542

.

ELECTRIC THROTTLE CONTROL ACTUATOR 

Refer to 

EC-490

, 

EC-494

, 

EC-500

 and 

EC-504

.

ASCD INDICATOR

Refer to 

EC-547

.

CAN COMMUNICATION

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CAN COMMUNICATION

System Description

INFOID:0000000001325903

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 speed 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 CAN 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-43, "CAN System Specification Chart"

, about CAN communication for detail.

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EVAPORATIVE EMISSION SYSTEM

EVAPORATIVE EMISSION SYSTEM

Description

INFOID:0000000001325904

SYSTEM DESCRIPTION

The evaporative emission system is used to reduce hydrocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplished by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into the EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not operating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating. EVAP canister purge volume control solenoid valve is controlled by ECM. When the
engine operates, the flow rate of vapor controlled by EVAP canister purge volume control solenoid valve is
proportionally regulated as the air flow increases.
EVAP canister purge volume control solenoid valve also shuts off the vapor purge line during decelerating and
idling.

PBIB1631E