Nissan Xterra. Instruction — part 225

EC-26

< SYSTEM DESCRIPTION >

[VQ40DE]

ELECTRIC IGNITION SYSTEM

ELECTRIC IGNITION SYSTEM

System Description

INFOID:0000000009483773

INPUT/OUTPUT SIGNAL CHART

*1: This signal is sent to the ECM via the CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.

SYSTEM DESCRIPTION

Firing order: 1-2-3-4-5-6

The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the

engine. The ignition timing data is stored in the ECM.

The ECM receives information such as the injection pulse width and camshaft position sensor (PHASE) sig-

nal. Computing this information, ignition signals are transmitted to the power transistor.

During the following conditions, the ignition timing is revised by the ECM according to the other data stored in

the ECM.

• At starting

• During warm-up

• At idle

• At low battery voltage

• During acceleration

The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed

within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not

operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.

The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.

Sensor

Input Signal to ECM

ECM function

Actuator

Crankshaft position sensor (POS)

Engine speed*

2

Piston position

Ignition timing
control

Power transistor

Camshaft position sensor (PHASE)

Mass air flow sensor

Amount of intake air

Engine coolant temperature sensor

Engine coolant temperature

Throttle position sensor

Throttle position

Accelerator pedal position sensor

Accelerator pedal position

Knock sensor

Engine knocking

Park/neutral position (PNP) switch (M/T)
TCM (A/T)

Gear position

Battery

Battery voltage*

2

Wheel sensor

Vehicle speed*

1

AIR CONDITIONING CUT CONTROL

EC-27

< SYSTEM DESCRIPTION >

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AIR CONDITIONING CUT CONTROL

Input/Output Signal Chart

INFOID:0000000009483774

*1: This signal is sent to the ECM via the CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.

System Description

INFOID:0000000009483775

This system improves engine operation when the air conditioner is used.

Under the following conditions, the air conditioner is turned off.

• When the accelerator pedal is fully depressed.

• When cranking the engine.

• At high engine speeds.

• When the engine coolant temperature becomes excessively high.

• When operating power steering during low engine speed or low vehicle speed.

• When engine speed is excessively low.

• When refrigerant pressure is excessively low or high.

Sensor

Input Signal to ECM

ECM function

Actuator

Air conditioner switch

Air conditioner ON signal*

1

Air conditioner
cut control

Air conditioner relay

Accelerator pedal position sensor

Accelerator pedal position

Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)

Engine speed*

2

Engine coolant temperature sensor

Engine coolant temperature

Battery

Battery voltage*

2

Refrigerant pressure sensor

Refrigerant pressure

Power steering pressure sensor

Power steering operation

Wheel sensor

Vehicle speed*

1

EC-28

< SYSTEM DESCRIPTION >

[VQ40DE]

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

System Description

INFOID:0000000009483776

INPUT/OUTPUT SIGNAL CHART

*: This signal is sent to the ECM via the CAN communication line.

BASIC ASCD SYSTEM

Refer to Owner's Instruction 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 the ASCD system, it automatically deactivates control.

NOTE:

Always drive vehicle in a 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.)

ACCELERATE 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 maintain 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 on ASCD steering switch are pressed at the same time (Set speed will be cleared)

• Brake pedal is depressed

• Clutch pedal is depressed or gear position is changed to the neutral position (M/T models)

• Selector lever position is changed to N, P or R (A/T models)

• 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 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 while ASCD is activated, all of ASCD operations will be canceled and vehicle

speed memory will be erased.

Sensor

Input signal to ECM

ECM function

Actuator

Brake pedal position switch

Brake pedal operation

ASCD vehicle speed control

Electric throttle control
actuator

Stop lamp switch

Brake pedal operation

Clutch pedal position switch

Clutch pedal operation

ASCD steering switch

ASCD steering switch operation

Park/Neutral position (PNP) switch
(M/T)
TCM (A/T)

Gear position

Wheel sensor

Vehicle speed*

TCM

Powertrain revolution*

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

EC-29

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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 maintain the new set speed.

RESUME OPERATION

When the RESUME/ACCELERATE switch is pressed after canceling operation other than depressing the

MAIN switch, vehicle speed will return to last set speed. To resume vehicle set speed, vehicle condition must

meet following conditions.

• Brake pedal is released

• Clutch pedal is released (M/T models)

• Selector lever position is in other than P and N (A/T models)

• Vehicle speed is greater than 40 km/h (25 MPH) and less than 144 km/h (89 MPH)

Component Description

INFOID:0000000009483777

ASCD STEERING SWITCH

Refer to

EC-395

.

BRAKE PEDAL POSITION SWITCH

Refer to

EC-398

and

EC-452

.

CLUTCH PEDAL POSITION SWITCH

Refer to

EC-398

and

EC-452

.

STOP LAMP SWITCH

Refer to

EC-398

,

EC-412

and

EC-452

.

ELECTRIC THROTTLE CONTROL ACTUATOR

Refer to

EC-426

,

EC-429

,

EC-433

and

EC-435

.

ASCD INDICATOR

Refer to

EC-458

.