2008 INFINITI FX35 Mass air flow sensor

TROUBLE DIAGNOSISEC-95
< SERVICE INFORMATION > [VQ35DE]
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Fail-Safe ChartINFOID:0000000001325929
When the DTC listed below is detected, the EC
M enters fail-safe mode and the MIL lights up.
 When there is an open circuit on MIL circuit, the ECM c annot warn the driver by MIL lighting up when there
is malfunction on engine control system.
Therefore, when electrical controlled throttle and pa rt of ECM related diagnoses are continuously detected
as NG for 5 trips, ECM warns the driver that engi ne control system malfunctions and MIL circuit is open by
means of operating fail-safe function.
The fail-safe function also operates when above diagnos es 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
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-III displays the engine coolant temperature decided by ECM.
Condition Engine coolant temperature decided
(CONSULT-III display)
Just as ignition switch is turned ON
or START 40
°C (104 °F)
Approx. 4 minutes or more after
engine 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.
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
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.
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 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
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.
So, the acceleration will be poor.
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EC-96
< SERVICE INFORMATION >[VQ35DE]
TROUBLE DIAGNOSIS
Symptom Matrix Chart
INFOID:0000000001325930
SYSTEM — BASIC ENGINE CONTROL SYSTEM
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut
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 2 EC-558
Fuel pressure regulator system 334444444 4EC-87
Fuel injector circuit 11232 22 2EC-552
Evaporative emission system 334444444 4EC-40
Air Positive crankcase ventilation sys-
tem 334444444 41
EC-51
Incorrect idle speed adjustment 1 1 1 1 1 EC-80
Electric throttle control actuator 112332222 2 2EC-494,
EC-504
IgnitionIncorrect ignition timing adjustment33111 11 1 EC-80
Ignition circuit 11222 22 2EC-569
Power supply and ground circuit 22333 33 23 EC-140
Mass air flow sensor circuit
1
12 2
222 2 EC-175,
EC-182
Engine coolant temperature sensor circuit
333
EC-193,
EC-204
Air fuel ratio (A/F) sensor EC-220
EC-220
EC-228
EC-236
EC-532
Throttle position sensor circuit
22EC-198
,
EC-302
,
EC-447
,
EC-449
,
EC-518
Accelerator pedal position sensor circuit 3 2 1 EC-424
,
EC-506
,
EC-512
,
EC-524
Knock sensor circuit 2 3 EC-315
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EC-98
< SERVICE INFORMATION >[VQ35DE]
TROUBLE DIAGNOSIS
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
5 FL-10
Fuel piping 5 5 5 5 5 5
EM-45
Va p o r l o c k —
Valve deposit 5 555 55 5 —
Poor fuel (Heavy weight gasoline,
Low octane) —
Air Air duct
55555 5 EM-17
Air cleaner
EM-17
Air leakage from air duct
(Mass air flow sensor — electric
throttle control actuator)
5555 EM-17
Electric throttle control actuator
EM-19
Air leakage from intake manifold/
Collector/GasketEM-19,
EM-24
Cranking Battery 111111
11
SC-4
Generator circuit
SC-19
Starter circuit 3SC-8
Signal plate 6EM-122
Park/neutral position (PNP)
switch4
AT- 1 0 2
Engine Cylinder head
55555 55 5 EM-100
Cylinder head gasket 4 3
Cylinder block
66666 66 6 4
EM-122
Piston
Piston ring
Connecting rod
Bearing
Crankshaft
Va l v e
mecha-
nism Timing chain
55555 55 5 EM-64
Camshaft
EM-83
Intake valve timing controlEM-64
Intake valve
3EM-100
Exhaust valve
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EC-114
< SERVICE INFORMATION >[VQ35DE]
TROUBLE DIAGNOSIS
51 L/W Mass air flow sensor[Engine is running]

Warm-up condition
 Idle speed 1.0 - 1.2V
[Engine is running]
 Warm-up condition
 Engine speed: 2,500 rpm 1.6 - 2.0V
55 W/R Heated oxygen sensor 2
(bank 2) [Engine is running]
 Revving engine from idle to 3,000 rpm quick-
ly after the following conditions are met
- Engine: After warming up
- Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load 0 - Approximately 1.0V
57 G A/F sensor 1 (Bank 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 2.6V
58 Y Approximately 2.3V
76 P Approximately 3.1V
77 BR Approximately 2.3V
60
61
62 PU
L
Y Ignition signal No. 5
Ignition signal No. 3
Ignition signal No. 1 [Engine is running]

Warm-up condition
 Idle speed NOTE:
The pulse cycle changes depending on rpm
at idle 0 - 0.2V
[Engine is running]
 Warm-up condition
 Engine speed: 2,500 rpm 0.1 - 0.4V
66 B Sensor ground
(Throttle position sensor) [Engine is running]

Warm-up condition
 Idle speed Approximately 0V
67 B/W Sensor ground [Engine is running]

Warm-up condition
 Idle speed Approximately 0V
68 BR Sensor power supply
(Power steering pressure
sensor) [Ignition switch: ON]
Approximately 5V
69 R Throttle position sensor 2 [Ignition switch: ON]
 Engine stopped
 Selector lever: D
 Accelerator pedal: Fully released
Less than 4.75V
[Ignition switch: ON]
 Engine stopped
 Selector lever: D
 Accelerator pedal: Fully depressed More than 0.36V
70 L/R Refrigerant pressure sensor [Engine is running]

Warm-up condition
 Both A/C switch and blower fan switch: ON (Compressor operates) 1.0 - 4.0V
TER-
MI-
NAL NO. WIRE
COLOR
ITEM CONDITION DATA (DC Voltage)
SEC986C
SEC987C
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EC-118
< SERVICE INFORMATION >[VQ35DE]
TROUBLE DIAGNOSIS
ItemDIAGNOSTIC TEST MODE
WORK SUP-
PORT SELF-DIAGNOSTIC
RESULTS DATA
MONI-
TOR ACTIVE
TEST DTC & SRT
CONFIRMATION
DTC*
1FREEZE FRAME
DATA*
1
SRT
STATUS DTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor (POS) ×××
Camshaft position sensor (PHASE) ×××
Mass air flow sensor ××
Engine coolant temperature sensor ××××
Air fuel ratio (A/F) sensor 1 ××××
Heated oxygen sensor 2 ××××
Vehicle speed sensor ×××
Accelerator pedal position sensor ××
Throttle position sensor ×××
Fuel tank temperature sensor ×××
EVAP control system pressure sen-
sor ××
Intake air temperature sensor ×××
Knock sensor ×
Refrigerant pressure sensor ×
Closed throttle position switch (ac-
celerator pedal position sensor sig-
nal) ×
Air conditioner switch ×
Park/neutral position (PNP) switch ××
Stop lamp switch ××
Power steering pressure sensor ××
Battery voltage ×
Load signal ×
Fuel level sensor ××
ICC steering switch ××
ASCD steering switch ××
ICC brake switch ××
ASCD brake switch ××
Snow mode switch ×
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TROUBLE DIAGNOSISEC-121
< SERVICE INFORMATION > [VQ35DE]
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*: The items are the same as those of 1st trip freeze frame data.
DATA MONITOR MODE
Monitored Item
×
: Applicable
INT/A TEMP SE
[° C] or [ °F]  The intake air temperature at the moment a malfunction is detected is displayed.
INT MANI PRES [kPa]  Always a certain value is displayed.
 These items are not efficient for S50 models.
FTFMCH1 Freeze frame data
item* Description
Monitored item Unit Description Remarks
ENG SPEED rpm  Indicates the engine speed computed from the sig-
nal of the crankshaft position sensor (POS) and
camshaft position sensor (PHASE).  Accuracy becomes poor if engine speed
drops below the idle rpm.
 If the signal is interrupted while the en-
gine is running, an abnormal value may
be indicated.
MAS A/F SE-B1 × The signal voltage of the mass air flow sensor is
displayed.  When the engine is stopped, a certain
value is indicated.
B/FUEL SCHDL × Base fuel schedule indicates the fuel injection
pulse width programmed into ECM, prior to any
learned on board correction.
A/F ALPHA-B1 %  The mean value of the air-fuel ratio feedback cor-
rection factor per cycle is indicated.  When the engine is stopped, a certain
value is indicated.
 This data also includes the data for the air-fuel ratio learning control.
A/F ALPHA-B2
×
COOLAN TEMP/S °C or ° The engine coolant temperature (determined by
the signal voltage of the engine coolant tempera-
ture sensor) is displayed.  When the engine coolant temperature
sensor is open or short-circuited, ECM
enters fail-safe mode. The engine cool-
ant temperature determined by the ECM
is displayed.
A/F SEN1 (B1) ×
 The A/F signal computed from the input signal of
the Air fuel ratio (A/F) sensor 1 is displayed.
A/F SEN1 (B2) ×
HO2S2 (B1) ×
 The signal voltage of the heated oxygen sensor 2 is
displayed.
HO2S2 (B2) ×
HO2S2 MNTR(B1) RICH/
LEAN  Display of heated oxygen sensor 2 signal:
RICH: means the amount of oxygen after three way
catalyst is relatively small.
LEAN: means the amount of oxygen after three
way catalyst is relatively large.  When the engine is stopped, a certain
value is indicated.
HO2S2 MNTR(B2) RICH/
LEAN
VHCL SPEED SE km/h or
mph  The vehicle speed computed from the vehicle
speed signal sent from combination meter is dis-
played.
BATTERY VOLT V  The power supply voltage of ECM is displayed.
ACCEL SEN 1 ×
 The accelerator pedal position sensor signal volt-
age is displayed.  ACCEL SEN 2 signal is converted by
ECM internally. Thus, it differs from ECM
terminal voltage signal.
ACCEL SEN 2
×
TP SEN 1-B1 V  The throttle position sensor signal voltage is dis-
played.  THRTL SEN 2 signal is converted by
ECM internally. Thus, it differs from ECM
terminal voltage signal.
TP SEN 2-B1 V
FUEL T/TMP SE
°C or ° The fuel temperature (determined by the signal
voltage of the fuel tank temperature sensor) is dis-
played.
INT/A TEMP SE °C or °F  The intake air temperature (determined by the sig-
nal voltage of the intake air temperature sensor) is
indicated.
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EC-122
< SERVICE INFORMATION >[VQ35DE]
TROUBLE DIAGNOSIS
EVAP SYS PRES V The signal voltage of EVAP control system pres-
sure sensor is displayed.
FUEL LEVEL SE V  The signal voltage of the fuel level sensor is dis-
played.
START SIGNAL × Indicates start signal status [ON/OFF] computed by
the ECM according to the signals of engine speed
and battery voltage.  After starting the engine, [OFF] is dis-
played regardless of the starter signal.
CLSD THL POS × Indicates idle position [ON/OFF] computed by ECM
according to the accelerator pedal position sensor
signal.
AIR COND SIG × Indicates [ON/OFF] condition of the air conditioner
switch as determined by the air conditioner signal.
P/N POSI SW × Indicates [ON/OFF] condition from the park/neutral
position (PNP) switch signal.
PW/ST SIGNAL × [ON/OFF] condition of the power steering system
(determined by the signal voltage of the power
steering pressure sensor) is indicated.
LOAD SIGNAL × Indicates [ON/OFF] condition from the electrical
load signal.
ON: Rear window defogger switch is ON and/or
lighting switch is in 2nd position.
OFF: Both rear window defogger switch and light-
ing switch are OFF.
IGNITION SW × Indicates [ON/OFF] condition from ignition switch
signal.
HEATER FAN SW × Indicates [ON/OFF] condition from the heater fan
switch signal.
BRAKE SW × Indicates [ON/OFF] condition from the stop lamp
switch signal.
INJ PULSE-B1 ×
 Indicates the actual fuel injection pulse width com-
pensated by ECM according to the input signals.  When the engine is stopped, a certain
computed value is indicated.
INJ PULSE-B2 ×
IGN TIMING × Indicates the ignition timing computed by ECM ac-
cording to the input signals.  When the engine is stopped, a certain
value is indicated.
CAL/LD VALUE %  Calculated load value indicates the value of the cur-
rent air flow divided by peak air flow.
MASS AIRFLOW g·m/s  Indicates the mass air flow computed by ECM ac-
cording to the signal voltage of the mass air flow
sensor.
PURG VOL C/V %  Indicates the EVAP canister purge volume control
solenoid valve control value computed by the ECM
according to the input signals.
 The opening becomes larger as the value increas- es.
INT/V TIM(B1) °CA
 Indicates [ °CA] of intake camshaft advanced angle.
INT/V TIM(B2) °CA
INT/V SOL(B1) %  The control condition of the intake valve timing con- trol solenoid valve (determined by ECM according
to the input signals) is indicated.
 The advance angle becomes larger as the value in-
creases.
INT/V SOL(B2) %
AIR COND RLY
× The air conditioner relay control condition (deter-
mined by ECM according to the input signals) is in-
dicated.
FUEL PUMP RLY × Indicates the fuel pump relay control condition de-
termined by ECM according to the input signals.
Monitored item Unit Description Remarks
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TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-131
< SERVICE INFORMATION > [VQ35DE]
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TROUBLE DIAGNOSIS - SPECIFICATION VALUE
DescriptionINFOID:0000000001325940
The specification (SP) value indicates the tolerance of
the value that is displayed in “SPEC” of “DATA MONI-
TOR” mode of CONSULT-III during normal operation of the Engine Control System. When the value in “SPEC”
of “DATA MONITOR” mode is within the SP value, the Engine Control System is confirmed OK. When the
value in “SPEC” of “DATA MONITOR” mode is NOT withi n the SP value, the Engine Control System may have
one or more malfunctions.
The SP value is used to detect malfunctions that may af fect the Engine Control System, but will not light the
MIL.
The SP value will be displayed for the following three items:
 B/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board correc- tion)
 A/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)
 MAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Testing ConditionINFOID:0000000001325941
 Vehicle driven distance: More than 5,000 km (3,107 miles)
 Barometric pressure: 98.3 - 104.3 kPa (1.003 - 1.064 kg/cm
2, 14.25 - 15.12 psi)
 Atmospheric temperature: 20 - 30 °C (68 - 86 °F)
 Engine coolant temperature: 75 - 95 °C (167 - 203 °F)
 Transmission: Warmed-up
- After the engine is warmed up to normal operating temperat ure, drive vehicle until “ATF TEMP 1” (A/T fluid
temperature sensor signal) indicates more than 60 °C (140 °F).
 Electrical load: Not applied
- Rear window defogger switch, air conditioner switch, li ghting switch are OFF. Steering wheel is straight
ahead.
 Engine speed: Idle
Inspection ProcedureINFOID:0000000001325942
NOTE:
Perform “SPEC” in “DATA MONITOR” mode in maximum scale display.
1. Perform EC-80, "
Basic Inspection".
2. Confirm that the testing conditions indicated above are met.
3. Select “B/FUEL SCHDL”, “A/F ALPHA-B1”, “A/F ALPHA-B2” and “MAS A/F SE-B1” in “SPEC” of “DATA
MONITOR” mode with CONSULT-III.
4. Make sure that monitor items are within the SP value.
5. If NG, go to EC-131, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000001325943
OVERALL SEQUENCE
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