Nissan Quest E52. Instruction — part 457
EC-38
< SYSTEM DESCRIPTION >
[VQ35DE]
SYSTEM
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.
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.
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.
SYSTEM
EC-39
< SYSTEM DESCRIPTION >
[VQ35DE]
C
D
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N
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MULTIPORT FUEL INJECTION SYSTEM
MULTIPORT FUEL INJECTION SYSTEM : System Description
INFOID:0000000009650957
SYSTEM DIAGRAM
INPUT/OUTPUT SIGNAL CHART
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
JMBIA1833GB
EC-40
< SYSTEM DESCRIPTION >
[VQ35DE]
SYSTEM
*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent to the ECM via the CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
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
by input signals (for engine speed and intake air) from the crankshaft position sensor (POS), camshaft position
sensor (PHASE) and the mass air flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated to improve engine performance under various operat-
ing conditions as listed below.
<Fuel increase>
• During warm-up
• When starting the engine
• During acceleration
• Hot-engine operation
• When selector lever position is changed from N to D
• High-load, high-speed operation
<Fuel decrease>
• During deceleration
• During high engine speed operation
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
Sensor
Input signal to ECM
ECM function
Actuator
Crankshaft position sensor (POS)
Engine speed*
3
Piston position
Fuel injection
& mixture ratio
control
Fuel injector
Camshaft position sensor (PHASE)
Mass air flow sensor
Amount of intake air
Intake air temperature sensor
Intake air temperature
Engine coolant temperature sensor
Engine coolant temperature
Air fuel ratio (A/F) sensor 1
Density of oxygen in exhaust gas
Throttle position sensor
Throttle position
Accelerator pedal position sensor
Accelerator pedal position
TCM
Gear position
Battery
Battery voltage*
3
Knock sensor
Engine knocking condition
Power steering pressure sensor
Power steering operation
Heated oxygen sensor 2*
1
Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit)
VDC/TCS operation command*
2
Combination meter
Vehicle speed*
2
BCM
Air conditioner operation*
2
PBIB3020E
SYSTEM
EC-41
< SYSTEM DESCRIPTION >
[VQ35DE]
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The mixture ratio feedback system provides the best air-fuel mixture ratio for drive ability and emission control.
The three way catalyst (manifold) can better reduce CO, HC and NOx emissions. This system uses A/F sen-
sor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The ECM adjusts the
injection pulse width according to the sensor voltage signal. For more information about A/F sensor 1, refer to
EC-27, "Air Fuel Ratio (A/F) Sensor 1"
. This maintains the mixture ratio within the range of stoichiometric
(ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the three way catalyst (manifold). Even if the switching
characteristics of A/F sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
• Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
- Deceleration and acceleration
- High-load, high-speed operation
- Malfunction of A/F sensor 1 or its circuit
- Insufficient activation of A/F sensor 1 at low engine coolant temperature
- High engine coolant temperature
- During warm-up
- After shifting from N to D
- When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., fuel injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes “short-term fuel trim” and “long-term fuel trim”.
“Short-term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from A/F sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the the-
oretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and an increase in
fuel volume if it is lean.
“Long-term fuel trim” is overall fuel compensation carried out over time to compensate for continual deviation
of the “short-term fuel trim” from the central value. Continual deviation will occur due to individual engine differ-
ences, wear over time and changes in the usage environment.
FUEL INJECTION TIMING
Two types of systems are used.
• Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycle according to the ignition order. This system is
used when the engine is running.
• Simultaneous Multiport Fuel Injection System
Fuel is injected simultaneously into all six cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The six injectors will then receive the signals 2 times for each engine cycle.
This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
SEF179U
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