Nissan Pathfinder. Manual - part 431

EC-30

< SYSTEM DESCRIPTION >

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SYSTEM

SYSTEM

ENGINE CONTROL SYSTEM
ENGINE CONTROL SYSTEM : System Description

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SYSTEM DIAGRAM

SYSTEM DESCRIPTION

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SYSTEM

EC-31

< SYSTEM DESCRIPTION >

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ECM controls the engine by various functions.

ENGINE CONTROL SYSTEM : Fail-safe

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NON DTC RELATED ITEM

DTC RELATED ITEM

Function

Reference

Multiport fuel injection system

EC-33, "MULTIPORT FUEL INJECTION SYSTEM : System De-
scription"

Electric ignition system

EC-35, "ELECTRIC IGNITION SYSTEM : System Description"

Air conditioning cut control

EC-36, "AIR CONDITIONING CUT CONTROL : System Descrip-
tion"

Automatic speed control device (ASCD)

EC-37, "AUTOMATIC SPEED CONTROL DEVICE (ASCD) : Sys-
tem Description"

Cooling fan control

EC-38, "COOLING FAN CONTROL : System Description"

Electronic controlled engine mount

EC-38, "ELECTRONIC CONTROLLED ENGINE MOUNT : Sys-
tem Description"

Evaporative emission system

EC-41, "EVAPORATIVE EMISSION SYSTEM : System Descrip-
tion"

Throttle control

EC-42, "THROTTLE CONTROL : System Description"

Intake valve timing control

EC-42, "INTAKE VALVE TIMING CONTROL : System Description"

Engine protection control at low engine oil pressure

EC-43, "ENGINE PROTECTION CONTROL AT LOW ENGINE 
OIL PRESSURE : System Description"

Fuel filler cap warning system

EC-44, "FUEL FILLER CAP WARNING SYSTEM : System De-
scription"

Variable induction air system

EC-45, "VARIABLE INDUCTION AIR SYSTEM : System Descrip-
tion"

Integrated control of engine, CVT, and ABS

EC-46, "INTEGRATED CONTROL OF ENGINE, CVT, AND ABS : 
System Description"

CAN communication

EC-46, "CAN COMMUNICATION : System Description"

Engine operating condi-

tion in fail-safe mode

Detected items

Remarks

Reference 

page

Engine speed will not 
rise more than 2,500 rpm 
due to the fuel cut

Malfunction indicator 
lamp circuit

When there is an open circuit on MIL circuit, the ECM cannot warn the 
driver by illuminating MIL when there is malfunction on engine control 
system.
Therefore, when electrical controlled throttle and part of ECM related 
diagnoses are continuously detected as NG for 5 trips, ECM warns the 
driver that engine control system malfunctions and MIL circuit is open 
by means of operating the fail-safe function.
The fail-safe function also operates when above diagnoses except MIL 
circuit are detected and demands the driver to repair the malfunction.

EC-443

DTC No.

Detected items

Engine operating condition in fail-safe mode

P0011

P0021

Intake valve timing control

The signal is not energized to the intake valve timing control solenoid valve and the valve 
control does not function.

P0101
P0102
P0103

Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.

EC-32

< SYSTEM DESCRIPTION >

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SYSTEM

P0117
P0118

Engine coolant tempera-
ture sensor circuit

Engine coolant temperature will be determined by ECM based on the following condition.
CONSULT displays the engine coolant temperature decided by ECM.

Condition

Engine coolant temperature decided 

(CONSULT display)

Just as ignition switch is turned ON 
or START

40

°C (104°F)

Approx 4 minutes or more after en-
gine starting

80

°C (176°F)

Except as shown above

40 - 80

°C (104 - 176°F)

(Depends on the time)

When the fail-safe system for engine coolant temperature sensor is activated, the cooling 
fan operates while engine is running.

P0122
P0123
P0222
P0223
P2135

Throttle position sensor

The ECM controls the electric throttle control actuator in regulating the throttle opening in 
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal 
condition.
Therefore, the acceleration will be poor. 

P0196
P0197
P0198

Engine oil temperature 
sensor

Intake valve timing control does not function.

P0500

Vehicle speed sensor

The cooling fan operates (Highest) while engine is running.

P0524

Engine oil pressure

• ECM illuminates oil pressure warning lamp on the combination meter.
• Engine speed will not rise more than 4,000 rpm due to the fuel cut.
• Fail-safe is canceled when ignition switch OFF 

→ ON.

P0605

ECM

(When ECM calculation function is malfunctioning:)
ECM stops the electric throttle control actuator control, throttle valve is maintained at a 
fixed opening (approx. 5 degrees) by the return spring.
ECM deactivates ASCD operation.

P0643

Sensor power supply

ECM stops the electric throttle control actuator control, throttle valve is maintained at a 
fixed opening (approx. 5 degrees) by the return spring.

P1805

Brake switch

ECM controls the electric throttle control actuator by regulating the throttle opening to a 
small range.
Therefore, acceleration will be poor.

Vehicle condition

Driving condition

When engine is idling

Normal

When accelerating

Poor acceleration

P2100
P2103

Throttle control motor relay ECM stops the electric throttle control actuator control, throttle valve is maintained at a 

fixed opening (approx. 5 degrees) by the return spring.

P2101

Electric throttle control 
function

ECM stops the electric throttle control actuator control, throttle valve is maintained at a 
fixed opening (approx. 5 degrees) by the return spring.

P2118

Throttle control motor

ECM stops the electric throttle control actuator control, throttle valve is maintained at a 
fixed opening (approx. 5 degrees) by the return spring.

DTC No.

Detected items

Engine operating condition in fail-safe mode

SYSTEM

EC-33

< SYSTEM DESCRIPTION >

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MULTIPORT FUEL INJECTION SYSTEM
MULTIPORT FUEL INJECTION SYSTEM : System Description

INFOID:0000000009178037

SYSTEM DIAGRAM

*1: ECM determines the start signal status by the signals of engine speed and battery voltage.

*2: This sensor is not used to control the engine system under normal conditions.

SYSTEM DESCRIPTION

The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of

time the valve remains open (injection pulse duration). The amount of fuel injected is a program value in the

ECM memory. The program value is preset by engine operating conditions. These conditions are determined

P2119

Electric throttle control ac-
tuator

(When electric throttle control actuator does not function properly due to the return spring 
malfunction:)
ECM controls the electric throttle actuator by regulating the throttle opening around the 
idle position. The engine speed will not rise more than 2,000 rpm.

(When throttle valve opening angle in fail-safe mode is not in specified range:)
ECM controls the electric throttle control actuator by regulating the throttle opening to 20 
degrees or less.

(When ECM detects the throttle valve is stuck open:)
While the vehicle is being driven, it slows down gradually because of fuel cut. After the 
vehicle stops, the engine stalls.
The engine can restart in the N or P position, and engine speed will not exceed 1,000 rpm 
or more.

P2122
P2123
P2127
P2128
P2138

Accelerator pedal position 
sensor

The ECM controls the electric throttle control actuator in regulating the throttle opening in 
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal 
condition.
Therefore, the acceleration will be poor. 

DTC No.

Detected items

Engine operating condition in fail-safe mode

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