Mass air flow INFINITI M35 2007 Factory Service Manual

EC-8Revision: 2007 April2007 M35/M45 .683
Wiring Diagram .....................................................684
Diagnostic Procedure ...........................................685
Component Inspection ..........................................689
IGNITION SIGNAL ..................................................691
Component Description ........................................691
Wiring Diagram .....................................................692
Diagnostic Procedure ...........................................697
Component Inspection ..........................................702
Removal and Installation ......................................703
REFRIGERANT PRESSURE SENSOR ..................704
Component Description ........................................704
Wiring Diagram .....................................................705
Diagnostic Procedure ...........................................706
Removal and Installation ......................................708
SNOW MODE SWITCH ...........................................709
Description ............................................................709
CONSULT-II Reference Value in the Data Monitor
Mode .....................................................................709
Wiring Diagram .....................................................710
Diagnostic Procedure ...........................................711
Component Inspection ..........................................713
MIL AND DATA LINK CONNECTOR ......................714
Wiring Diagram .....................................................714
SERVICE DATA AND SPECIFICATIONS (SDS) ....716
Fuel Pressure .......................................................716
Idle Speed and Ignition Timing .............................716
Calculated Load Value ..........................................716
Mass Air Flow Sensor ...........................................716
Intake Air Temperature Sensor .............................716
Engine Coolant Temperature Sensor ...................716
Fuel Tank Temperature Sensor ............................716
Crankshaft Position Sensor (POS) .......................716
Camshaft Position Sensor (PHASE) ....................716
A/F Sensor 1 Heater .............................................716
Heated Oxygen Sensor 2 Heater .........................717
Throttle Control Motor ...........................................717
Fuel Injector ..........................................................717
Fuel Pump ............................................................717
VK45DE
INDEX FOR DTC .....................................................718
DTC No. Index ......................................................718
Alphabetical Index ................................................722
PRECAUTIONS .......................................................726
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” ...............................................................726
Precautions for Procedures without Cowl Top Cover .726
On Board Diagnostic (OBD) System of Engine and
A/T ........................................................................726
Precaution ............................................................727
PREPARATION .......................................................730
Special Service Tools ...........................................730
Commercial Service Tools ....................................731
ENGINE CONTROL SYSTEM ................................732
System Diagram ...................................................732
Multiport Fuel Injection (MFI) System ...................733Electronic Ignition (EI) System ..............................735
Fuel Cut Control (At No Load and High Engine
Speed) ..................................................................736
AIR CONDITIONING CUT CONTROL ....................737
Input/Output Signal Chart .....................................737
System Description ...............................................737
AUTOMATIC SPEED CONTROL DEVICE (ASCD) .738
System Description ...............................................738
Component Description ........................................739
CAN COMMUNICATION .........................................740
System Description ...............................................740
EVAPORATIVE EMISSION SYSTEM .....................741
Description ............................................................741
Component Inspection ..........................................744
Removal and Installation .......................................745
How to Detect Fuel Vapor Leakage ......................745
ON BOARD REFUELING VAPOR RECOVERY
(ORVR) ....................................................................748
System Description ...............................................748
Diagnostic Procedure ............................................749
Component Inspection ..........................................751
POSITIVE CRANKCASE VENTILATION ................753
Description ............................................................753
Component Inspection ..........................................753
IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM-
NATS) ......................................................................755
Description ............................................................755
ON BOARD DIAGNOSTIC (OBD) SYSTEM ...........756
Introduction ...........................................................756
Two Trip Detection Logic .......................................756
Emission-Related Diagnostic Information .............757
Malfunction Indicator Lamp (MIL) .........................772
OBD System Operation Chart ...............................774
BASIC SERVICE PROCEDURE .............................780
Basic Inspection ....................................................780
Idle Speed and Ignition Timing Check ..................785
Procedure After Replacing ECM ...........................787
VIN Registration ....................................................787
Accelerator Pedal Released Position Learning .....788
Throttle Valve Closed Position Learning ...............788
Idle Air Volume Learning .......................................788
Fuel Pressure Check ............................................790
TROUBLE DIAGNOSIS ..........................................792
Trouble Diagnosis Introduction .............................792
DTC Inspection Priority Chart ...............................798
Fail-Safe Chart ......................................................800
Symptom Matrix Chart ..........................................801
Engine Control Component Parts Location ...........805
Vacuum Hose Drawing .........................................814
Circuit Diagram .....................................................815
ECM Harness Connector Terminal Layout ............817
ECM Terminals and Reference Value ...................817
CONSULT-II Function (ENGINE) ..........................826
Generic Scan Tool (GST) Function .......................838
CONSULT-II Reference Value in Data Monitor .....841
Major Sensor Reference Graph in Data Monitor
Mode .....................................................................845
TROUBLE DIAGNOSIS - SPECIFICATION VALUE .847
Description ............................................................847

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Revision: 2007 April2007 M35/M45 Wiring Diagram ...................................................1390
Diagnostic Procedure ..........................................1391
Component Inspection ........................................1394
Removal and Installation .....................................1394
FUEL PUMP ..........................................................1395
Description ..........................................................1395
CONSULT-II Reference Value in Data Monitor Mode
1395
Wiring Diagram ...................................................1396
Diagnostic Procedure ..........................................1397
Component Inspection ........................................1401
Removal and Installation .....................................1402
ICC BRAKE SWITCH ............................................1403
Component Description .......................................1403
CONSULT-II Reference Value in Data Monitor Mode
1403
Wiring Diagram ...................................................1404
Diagnostic Procedure ..........................................1405
Component Inspection ........................................1410
IGNITION SIGNAL .................................................1411
Component Description .......................................1411
Wiring Diagram ...................................................1412
Diagnostic Procedure ..........................................1417
Component Inspection ........................................1421
Removal and Installation .....................................1423
REFRIGERANT PRESSURE SENSOR ................1424
Component Description .......................................1424
Wiring Diagram ...................................................1425Diagnostic Procedure ..........................................1426
Removal and Installation .....................................1428
VIAS .......................................................................1429
Description ...........................................................1429
CONSULT-II Reference Value in Data Monitor Mode
1430
Wiring Diagram ....................................................1431
Diagnostic Procedure ..........................................1433
Component Inspection .........................................1436
Removal and Installation .....................................1437
MIL AND DATA LINK CONNECTOR .....................1438
Wiring Diagram ....................................................1438
SERVICE DATA AND SPECIFICATIONS (SDS) ...1440
Fuel Pressure ......................................................1440
Idle Speed and Ignition Timing ............................1440
Calculated Load Value .........................................1440
Mass Air Flow Sensor ..........................................1440
Intake Air Temperature Sensor ............................1440
Engine Coolant Temperature Sensor ..................1440
Fuel Tank Temperature Sensor ...........................1440
Crankshaft Position Sensor (POS) ......................1440
Camshaft Position Sensor (PHASE) ...................1440
A/F Sensor 1 Heater ............................................1440
Heated Oxygen Sensor 2 Heater ........................1441
Throttle Control Motor ..........................................1441
Fuel Injector .........................................................1441
Fuel Pump ...........................................................1441

EC-26
[VQ35DE]
PRECAUTIONS
Revision: 2007 April2007 M35/M45

Before replacing ECM, perform ECM Terminals and Refer-
ence Value inspection and make sure ECM functions prop-
erly. Refer to EC-114, "
ECM Terminals and Reference Value"
.

Handle mass air flow sensor carefully to avoid damage.

Do not clean mass air flow sensor with any type of deter-
gent.

Do not disassemble electric throttle control actuator.

Even a slight leak in the air intake system can cause seri-
ous incidents.

Do not shock or jar the camshaft position sensor (PHASE),
crankshaft position sensor (POS).

After performing each TROUBLE DIAGNOSIS, perform DTC
Confirmation Procedure or Overall Function Check.
The DTC should not be displayed in the DTC Confirmation
Procedure if the repair is completed. The Overall Function
Check should be a good result if the repair is completed.

When measuring ECM signals with a circuit tester, never
allow the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.

Do not use ECM ground terminals when measuring input/
output voltage. Doing so may result in damage to the ECM's
transistor. Use a ground other than ECM terminals, such as
the ground.
MEF040D
SEF217U
SEF348N

ENGINE CONTROL SYSTEM
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Multiport Fuel Injection (MFI) SystemNBS004S3
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent to the ECM through 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 is changed from N to D

High-load, high-speed operation
<Fuel decrease>

During deceleration

During high engine speed operation
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
3
Piston position
Fuel injection
& mixture ratio
controlFuel injector Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
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
Park/neutral position (PNP) switch Gear position
Battery
Battery voltage*
3
Knock sensor Engine knocking condition
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit)
VDC/TCS operation command*
2
Air conditioner switch
Air conditioner operation*2
Wheel sensor
Vehicle speed*2

EC-32
[VQ35DE]
ENGINE CONTROL SYSTEM
Revision: 2007 April2007 M35/M45
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst 1 can then better reduce CO, HC and NOx emissions. This system uses A/F sensor 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-244,
"DTC P0131, P0151 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 1. Even if the switching characteris-
tics of A/F sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal from heated oxygen sen-
sor 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 long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
PBIB3020E

ENGINE CONTROL SYSTEM
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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 firing 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 fuel injectors will then receive the signals two 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.
FUEL SHUT-OFF
Fuel to each cylinder is cut off during deceleration, operation of the engine at excessively high speeds or oper-
ation of the vehicle at excessively high speeds.
Electronic Ignition (EI) SystemNBS004S4
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through 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
SEF179U
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
2
Piston position
Ignition timing
controlPower 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
Battery
Battery voltage*
2
Knock sensor Engine knocking
Park/neutral position (PNP) switch Gear position
Wheel sensor
Vehicle speed*
1

EC-96
[VQ35DE]
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
DTC Inspection Priority ChartNBS004SZ
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:

If DTC U1000 or U1001 is displayed with other DTC, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-161, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .

If DTC U1010 is displayed with other DTC, first perform the trouble diagnosis for DTC U1010. Refer
to EC-164, "
DTC U1010 CAN COMMUNICATION" .
Priority Detected items (DTC)
1

U1000 U1001 CAN communication line

U1010 CAN communication

P0101 P0102 P0103 Mass air flow sensor

P0112 P0113 P0127 Intake air temperature sensor

P0117 P0118 P0125 Engine coolant temperature sensor

P0122 P0123 P0222 P0223 P1225 P1226 P2135 Throttle position sensor

P0128 Thermostat function

P0181 P0182 P0183 Fuel tank temperature sensor

P0327 P0328 Knock sensor

P0335 Crankshaft position sensor (POS)

P0340 P0345 Camshaft position sensor (PHASE)

P0460 P0461 P0462 P0463 Fuel level sensor

P0500 Vehicle speed sensor

P0643 Sensor power supply

P0605 ECM

P0700 TCM

P0705 P0850 Park/Neutral position (PNP) switch

P1550 P1551 P1552 P1553 P1554 Battery current sensor

P1610 - P1615 NATS

P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor

EC-98
[VQ35DE]
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
Fail-Safe ChartNBS004T0
When the DTC listed below is detected, the ECM enters fail-safe mode and the MIL lights up.

When there is an open circuit on MIL circuit, the ECM cannot warn the driver by lighting up 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 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.
DTC No. Detected items Engine operating condition in fail-safe mode
P0102
P0103Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0117
P0118Engine coolant tempera-
ture sensor circuitEngine coolant temperature will be determined by ECM based on the time after turning
ignition switch ON or START.
CONSULT-II displays the engine coolant temperature decided by ECM.
ConditionEngine coolant temperature decided
(CONSULT-II display)
Just as ignition switch is turned
ON or START40°C (104°F)
More than approx. 4 minutes after
ignition ON or START80°C (176°F)
Except as shown above40 - 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
P2135Throttle 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.
So, the acceleration will be poor.
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.
P2100
P2103Throttle 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
functionECM 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.
P2119 Electric throttle control
actuator(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 driving, it slows down gradually by fuel cut. After the vehicle stops,
the engine stalls.
The engine can restart in N or P position, and engine speed will not exceed 1,000 rpm or
more.
P2122
P2123
P2127
P2128
P2138Accelerator pedal position
sensorThe 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.
So, the acceleration will be poor.
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut

TROUBLE DIAGNOSIS
EC-99
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Revision: 2007 April2007 M35/M45
Symptom Matrix ChartNBS004T1
SYSTEM — BASIC ENGINE CONTROL SYSTEM
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel pump circuit 11232 22 3 2EC-675
Fuel pressure regulator system334444444 4EC-88
Fuel injector circuit 11232 22 2EC-669
Evaporative emission system334444444 4EC-39
Air Positive crankcase ventilation sys-
tem
334444444 41EC-51
Incorrect idle speed adjustment 1 1 1 1 1EC-78
Electric throttle control actuator 112332222 2 2EC-
604,EC-
598 ,EC-
610 ,EC-
615
IgnitionIncorrect ignition timing adjustment33111 11 1EC-78
Ignition circuit 11222 22 2EC-691
Main power supply and ground circuit22333 33 23EC-154
Mass air flow sensor circuit
1
122
222 2EC-193,
EC-202
Engine coolant temperature sensor circuit
333EC-214,
EC-226
Air fuel ratio (A/F) sensor 1 circuitEC-234
,
EC-244
,
EC-253
,
EC-262
,
EC-646
Throttle position sensor circuit
22EC-219
,
EC-342
,
EC-518
,
EC-520
,
EC-631
Accelerator pedal position sensor circuit 3 2 1EC-
617,EC-
624 ,EC-
638 ,EC-
486
Knock sensor circuit 2 3EC-359
Crankshaft position sensor (POS) circuit 2 2EC-364

TROUBLE DIAGNOSIS
EC-101
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SYSTEM — ENGINE MECHANICAL & OTHER
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel tank
5
5FL-10
Fuel piping 5 5 5 5 5 5EM-47
Vapor lock—
Valve deposit
5 555 55 5—
Poor fuel (Heavy weight gaso-
line, Low octane)—
Air Air duct
55555 5EM-19
Air cleanerEM-19
Air leakage from air duct
(Mass air flow sensor — electric
throttle control actuator)
5555EM-19
Electric throttle control actuatorEM-21
Air leakage from intake manifold/
Collector/GasketEM-26
Cranking Battery
111111
11SC-4
Generator circuitSC-20
Starter circuit 3SC-8
Signal plate 6EM-124
PNP switch 4AT- 11 3
Engine Cylinder head
55555 55 5EM-102
Cylinder head gasket 4 3
Cylinder block
66666 66 64
EM-124
Piston
Piston ring
Connecting rod
Bearing
Crankshaft
Va l v e
mecha-
nismTiming chain
55555 55 5EM-66
CamshaftEM-85
Intake valve timing controlEM-66
Intake valve
3EM-85
Exhaust valve