EC-562
< SYSTEM DESCRIPTION >[VQ35DE]
COMPONENT PARTS
Refrigerant Pressure Sensor
INFOID:0000000009462508
The refrigerant pressure sensor is installed at the c ondenser of the air conditioner system. The sensor uses an
electrostatic volume pressure transducer to convert refrigerant pressure to voltage. The voltage signal is sent
to ECM, and ECM controls cooling fan system.
Stop Lamp Switch & Brake Pedal Position SwitchINFOID:0000000009462509
Stop lamp switch and brake pedal position switch are installed to brake pedal bracket.
ECM detects the state of the brake pedal by those two types of input (ON/OFF signal).
VIAS Control Solenoid Valve 1 and 2INFOID:0000000009462510
The VIAS control solenoid valve cuts the intake manifold vacuum signal for power valve control. It responds to
ON/OFF signals from the ECM. When the solenoid is OFF, the vacuum signal from the intake manifold is cut.
When the ECM sends an ON signal the coil pulls the plunger downward and sends the vacuum signal to the
power valve actuator.
PBIB2657E
Brake pedal Brake pedal position switch Stop lamp switch
Released ON OFF
Depressed OFF ON
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EC-566
< SYSTEM DESCRIPTION >[VQ35DE]
SYSTEM
ECM controls the engine by various functions.
ENGINE CONTROL SYSTEM : Fail-safeINFOID:0000000009462514
NON DTC RELATED ITEM
DTC RELATED ITEM
Function Reference
Multiport fuel injection system EC-568, "MULTIPORT FUEL INJE
CTION SYSTEM : System De-
scription"
Electric ignition system EC-571, "ELECTRIC IGNITION SYSTEM : System Description"
Air conditioning cut control EC-573, "AIR CONDITIONING CUT
CONTROL : System Descrip-tion"
Automatic speed control device (ASCD) EC-574, "AUTOMATIC SPEED CONTROL DEVICE (ASCD) : System Description"
Cooling fan control
EC-575, "COOLING FAN CONTROL : System Description"
Electronic controlled engine mount EC-577, "ELECTRONIC CONTROLLED ENGINE MOUNT : Sys-tem Description"
Evaporative emission systemEC-580, "EVAPORATIVE EMISSI
ON SYSTEM : System Descrip-tion"
Throttle control EC-581, "THROTTLE CONTROL : System Description"
Intake valve timing control EC-583, "INTAKE VALVE TIMING
CONTROL : System Descrip-tion"
Engine protection control at low engine oil pressure EC-583, "ENGINE PROTECTION
CONTROL AT LOW ENGINE OIL PRESSURE : System Description"
Fuel filler cap warning system EC-585, "FUEL FILLER CAP WARNING SYSTEM : System De-scription"
Variable induction air systemEC-586, "VARIABLE INDUCTION AI
R SYSTEM : System Descrip-tion"
Integrated control of engine, CVT, and ABS EC-588, "INTEGRATED CONTROL OF ENGINE, CVT, AND ABS : System Description"
Alternator power generation voltage variable control systemEC-588, "ALTERNATOR POWER GENERATION VOLTAGE VARIABLE CONTROL SYSTEM
: System Description"
CAN communication EC-588, "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-973
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.
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SYSTEMEC-567
< SYSTEM DESCRIPTION > [VQ35DE]
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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 th rottle 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
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EC-568
< SYSTEM DESCRIPTION >[VQ35DE]
SYSTEM
MULTIPORT FUEL INJECTION SYSTEM
MULTIPORT FUEL INJECTION SY
STEM : System DescriptionINFOID:0000000009462515
SYSTEM DIAGRAM
*1: Automatic air conditioning system
*2: Manual air conditioning system
INPUT/OUTPUT SIGNAL CHART
P2119 Electric thro ttle 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
JSBIA2683GB
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SYSTEMEC-569
< SYSTEM DESCRIPTION > [VQ35DE]
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*1: ECM determines the start signal status
by the signals of engine speed and battery voltage.
*2: This sensor is not used to contro l the engine system under normal conditions.
*3: Automatic air conditioning system
*4: Manual air conditioning system
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). T he amount of fuel injected is a program value in the
ECM memory. The program value is preset by engi ne operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from t he 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 compens ated to improve engine performance under various operat-
ing conditions as listed below.
• 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
• During deceleration
• During high engine speed operation
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed
*1
Fuel injection
& mixture ratio
control Fuel injector
Camshaft position sensor (PHASE) Piston position
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
Transmission range switch Gear position
Battery Battery voltage
*1
Knock sensor Engine knocking condition
Heated oxygen sensor 2
*2Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit) • VDC operation signal
• TCS operation signal
CAN communi-
cation
Power steering control module EPS operation signal
Combination meter Vehicle speed signal
A/C auto amp.
*3• A/C ON signal
• Blower fan ON signal
BCM
*4
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
EC-570
< SYSTEM DESCRIPTION >[VQ35DE]
SYSTEM
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system prov
ides 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-552, "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 th ree 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 t he mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM c ontrols the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mi xture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass ai r 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 co mpared 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 compensati on 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 carri ed 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.
PBIB3020E
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EC-572
< SYSTEM DESCRIPTION >[VQ35DE]
SYSTEM
*: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
Ignition 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 si gnals are transmitted to the power transistor.
During the following conditions, the ignition timing is re vised 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.
AIR CONDITIONING CUT CONTROL
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed
*
Ignition timing
control Ignition coil
(with power transistor)
Camshaft position sensor
(PHASE) Piston position
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
Transmission range switch Gear position
Battery Battery voltage
*
Knock sensor Engine knocking
Combination meter Vehicle speed CAN communi-
cation
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SYSTEMEC-573
< SYSTEM DESCRIPTION > [VQ35DE]
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AIR CONDITIONING CUT CONTROL : System DescriptionINFOID:0000000009462517
SYSTEM DIAGRAM
*1: Automatic air conditioning system
*2: Manual air conditioning system
INPUT/OUTPUT SIGNAL CHART
*1: ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: Automatic air conditioning system
*3: Manual air conditioning system
SYSTEM DESCRIPTION
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.
JSBIA2685GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed
*1
Air conditioner
cut control IPDM E/R
↓
Air conditioner relay
↓
Compressor
Camshaft position sensor (PHASE)
Engine coolant temperature sensor Engine coolant temperature
Accelerator pedal position sensor Accelerator pedal position
Battery Battery voltage*1
Refrigerant pressure sensor Refrigerant pressure
Power steering control module EPS operation signal
CAN communi-
cation line
Combination meter Vehicle speed signal
A/C auto amp.
*2• A/C ON signal
• Blower fan ON signal
BCM
*3
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM