2008 INFINITI FX35 Mass air flow sensor

DTC P0112, P0113 IAT SENSOREC-777
< SERVICE INFORMATION > [VK45DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
Refer to
EC-723, "Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK INTAKE AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT
1. Disconnect mass air flow sensor (intake air temperature sensor is built-into) (1) harness connector.
2. Turn ignition switch ON.
3. Check voltage between mass air flow sensor terminal 5 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
3.CHECK INTAKE AIR TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between mass air flow sensor terminal 6 and ECM terminal 67. Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to EC-778, "
Component Inspection".
OK or NG
OK >> GO TO 5.
NG >> Replace mass air flow sensor ( with intake air temperature sensor).
PBIB2195E
PBIB3230E
Voltage: Approximately 5V
PBIB1169E
Continuity should exist.
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-778
< SERVICE INFORMATION >[VK45DE]
DTC P0112, P0113 IAT SENSOR
5.CHECK INTERMITTENT INCIDENT
Refer to EC-717
.
>> INSPECTION END
Component InspectionINFOID:0000000001326608
INTAKE AIR TEMPERATURE SENSOR
1. Check resistance between intake air temperature terminals 5
and 6 under the following conditions.
2. If NG, replace mass air flow sensor (with intake air temperature sensor).
Removal and InstallationINFOID:0000000001326609
MASS AIR FLOW SENSOR
Refer to EM-173.
Intake air temperature °C ( °F) Resistance k Ω
25 (77) 1.800 - 2.200
PBIB1604E
SEF012P
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0127 IAT SENSOREC-793
< SERVICE INFORMATION > [VK45DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
DTC P0127 IAT SENSOR
Component DescriptionINFOID:0000000001326631
The intake air temperature sensor is
built into mass air flow sensor.
The sensor detects intake air temperature and transmits a signal to
the ECM.
The temperature sensing unit uses a thermistor which is sensitive to
the change in temperature. Electric al resistance of the thermistor
decreases in response to the temperature rise.

*: These data are reference values and are measured between ECM terminal 34
(Intake air temperature sensor) and ground.
CAUTION:
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 te rminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000001326632
DTC Confirmation ProcedureINFOID:0000000001326633
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
CAUTION:
Always drive vehicle at a safe speed.
TESTING CONDITION:
This test may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road
test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-III
1. Wait until engine coolant temperature is less than 90 °C (194 °F)
a. Turn ignition switch ON.
b. Select “DATA MONITOR” mode with CONSULT-III.
c. Check the engine coolant temperature.
d. If the engine coolant temperature is not less than 90 °C (194 °F), turn ignition switch OFF and cool down
engine.
 Perform the following steps before engine coolant temperature is above 90 °C (194 °F).
2. Start engine.
PBIB1604E
Intake air temperature °C ( °F) Voltage* V Resistance k
Ω
25 (77) 3.3 1.800 - 2.200
80 (176) 1.2 0.283 - 0.359
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0127
0127 Intake air temperature
too high Rationally incorrect voltage from the sensor is
sent to ECM, compared with the voltage signal
from engine coolant temperature sensor.  Harness or connectors
(The sensor circuit is open or shorted)
 Intake air temperature sensor
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-794
< SERVICE INFORMATION >[VK45DE]
DTC P0127 IAT SENSOR
3. Hold vehicle speed at more than 70 km/h (43 MPH) for 100 consecutive seconds.
4. Check 1st trip DTC.
5. If 1st trip DTC is detected, go to
EC-794, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001326634
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-723, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to EC-778, "
Component Inspection".
OK or NG
OK >> GO TO 3.
NG >> Replace mass air flow sensor (with intake air temperature sensor).
3.CHECK INTERMITTENT INCIDENT
Refer to EC-717
.
Refer to EC-776, "
Wiring Diagram".
>> INSPECTION END
Component InspectionINFOID:0000000001326635
INTAKE AIR TEMPERATURE SENSOR
1. Check resistance between intake air temperature sensor termi-
nals 5 and 6 under the following conditions.
2. If NG, replace mass air flow sensor (with intake air temperature sensor).
PBIB2195E
Intake air temperature °C ( °F) Resistance k Ω
25 (77) 1.800 - 2.200
PBIB1604E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0127 IAT SENSOREC-795
< SERVICE INFORMATION > [VK45DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
Removal and InstallationINFOID:0000000001326636
MASS AIR FLOW SENSOR
Refer to
EM-173.
SEF012P
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-822
< SERVICE INFORMATION >[VK45DE]
DTC P0133, P0153
A/F SENSOR 1
DTC P0133, P0153 A/F SENSOR 1
Component DescriptionINFOID:0000000001326664
The air fuel ratio (A/F) sensor 1 is a planar dual-cell limit current sen-
sor. The sensor element of the A/F sensor 1 is the combination of a
Nernst concentration cell (sensor cell) with an oxygen-pump cell,
which transports ions. It has a heater in the element.
The sensor is capable of precise measurement = 1, but also in the
lean and rich range. Together with its control electronics, the sensor
outputs a clear, continuous signal throughout a wide range (0.7 <
< air).
The exhaust gas components diffuse through the diffusion gap at the
electrode of the oxygen pump and Nernst concentration cell, where
they are brought to thermodynamic balance.
An electronic circuit controls the pump current through the oxygen-
pump cell so that the composition of the exhaust gas in the diffusion
gap remains constant at = 1. Ther efore, the A/F sensor 1 is able to
indicate air/fuel ratio by this pumping of current. In addition, a heater
is integrated in the sensor to ensure the required operating tempera-
ture of 700 - 800 °C (1,292 - 1,472 °F).
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001326665
Specification data are reference values.
On Board Diagn osis LogicINFOID:0000000001326666
To judge the malfunction of A/F sensor 1, this diagnosis measures response time of the A/F signal computed
by ECM from the A/F sensor 1 signal. The time is compensated by engine operating (speed and load), fuel
feedback control constant, and the A/F sensor 1 temper ature index. Judgment is based on whether the com-
pensated time (the A/F signal cycling time index) is inordinately long or not.
DTC Confirmation ProcedureINFOID:0000000001326667
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
SEF579Z
SEF580Z
MONITOR ITEM CONDITION SPECIFICATION
A/F SEN1 (B1)
A/F SEN1 (B2)  Engine: After warming up Maintaining engine speed at 2,000 rpm Fluctuates around 1.5 V
DTC No. Trouble diagnosis name DTC detecting condition Possible Cause
P0133
0133
(Bank 1)
Air fuel ratio (A/F) sensor 1
circuit slow response The response of the A/F signal computed by ECM
from A/F sensor 1 signal takes more than the
specified time.  Harness or connectors
(The A/F sensor 1 circuit is open or
shorted.)
 A/F sensor 1
 A/F sensor 1 heater
 Fuel pressure
 Fuel injector
 Intake air leaks
 Exhaust gas leaks
PCV
 Mass air flow sensor
P0153
0153
(Bank 2)
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0133, P0153 A/F SENSOR 1
EC-823
< SERVICE INFORMATION > [VK45DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
TESTING CONDITION:
Before performing the following procedure, confirm
that battery voltage is more than 11V at idle.
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1minute under no load.
4. Let engine idle for 1 minute.
5. Select “A/F SEN1(B1) P1278/P1279” (for DTC P0133) or “A/F SEN1(B2) P1288/P1289” (for DTC P0153)
of “A/F SEN1” in “DTC WORK SUPPORT” mode with CONSULT-III.
6. Touch “START”. If “COMPLETED” appears on CONSULT-III screen, go to step 10.
If “COMPLETED” does not appear on CONSULT- III screen, go to the following step.
7. After perform the following procedure, “TESTIN G” will be displayed on the CONSULT-III screen.
a. Increase the engine speed up to 4,000 to 5,000 rpm and keep it for 10 seconds.
b. Fully release accelerator pedal and then let engine idle for about 10 seconds. If “TESTING” is not displayed after 10 seconds, refer to EC-709
.
8. Wait for about 20 seconds at idle at under the condi tion that “TESTING” is displayed on the CONSULT-III
screen.
9. Make sure that “TESTING” changes to “COMPLETED”. If “TESTING” changed to “OUT OF CONDITION”, refer to EC-709
.
10. Make sure that “OK” is display ed after touching “SELF-DIAG RESULT”.
If “NG” is displayed, go to EC-827, "
Diagnosis Procedure".
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Select Service $01 with GST.
3. Calculate the total value of “Short term f uel trim” and “Long term fuel trim” indications.
Make sure that the total percentage should be within ±15%.
If OK, go to the following step.
If NG, check the following.
 Intake air leaks
 Exhaust gas leaks
 Incorrect fuel pressure
 Lack of fuel
 Fuel injector
 Incorrect PCV hose connection
 PCV valve
 Mass air flow sensor
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1minute under no load.
6. Let engine idle for 1 minute.
7. Increase the engine speed up to 4,000 to 5,000 rpm and keep it for 10 seconds.
8. Fully release accelerator pedal and then let engine idle for about 1 minute.
9. Select Service $07 with GST. If the 1st trip DTC is displayed, go to EC-827, "
Diagnosis Procedure".
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-828
< SERVICE INFORMATION >[VK45DE]
DTC P0133, P0153
A/F SENSOR 1
>> GO TO 3.
3.CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
OK or NG
OK >> GO TO 4.
NG >> Repair or replace.
4.CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace.
5.CLEAR THE SELF-LEARNING DATA
With CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CONSULT-III.
3. Clear the self-learning control coeffi cient by touching “CLEAR” or “START”.
4. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P172, P0174 or P0175 detected? Is it difficult to start engine?
Without CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor (1) harness connector.
4. Restart engine and let it idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor harness con- nector.
6. Make sure DTC P0102 is displayed.
7. Erase the DTC memory. Refer to EC-633, "
Emission-related
Diagnostic Information".
8. Make sure DTC P0000 is displayed.
9. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-861 or EC-871.
No >> GO TO 6.
6.CHECK A/F SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect A/F sensor 1 harness connector. Tightening torque: 50 N-m (5.1 kg-m, 37 ft-lb)
PBIB1216E
PBIB3230E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C