2008 INFINITI FX35 Mass air flow sensor

DTC P0112, P0113 IAT SENSOREC-189
< SERVICE INFORMATION > [VQ35DE]
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DTC P0112, P0113 IAT SENSOR
Component DescriptionINFOID:0000000001326006
The intake air temperature (IAT) 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.

*: This data is reference values and is 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:0000000001326007
DTC Confirmation ProcedureINFOID:0000000001326008
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.
1. Turn ignition switch ON and wait at least 5 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-190, "
Diagnosis Procedure".
PBIB1604E
Intake air temperature
°C ( °F) Voltage* V Resistance k
Ω
25 (77) 3.30 1.800 - 2.200
80 (176) 1.22 0.283 - 0.359
SEF012P
DTC No. Trouble diagnosis
name DTC detecting condition Possible cause
P0112
0112 Intake air tempera-
ture sensor circuit
low input An excessively low voltage from the sensor is
sent to ECM.
 Harness or connectors
(Intake air temperature sensor circuit is open
or shorted.)
 Intake air temperature sensor
P0113
0113 Intake air tempera-
ture sensor circuit
high input An excessively high voltage from the sensor is
sent to ECM.
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3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0112, P0113 IAT SENSOREC-191
< SERVICE INFORMATION > [VQ35DE]
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2. Loosen and retighten ground screw on the body. Refer to
EC-144, "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 (with intake air temperature sensor) harness connector.
2. Turn ignition switch ON.
3. Check voltage between mass air flow sensor terminal 5 and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair 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-192, "
Component Inspection".
OK or NG
OK >> GO TO 5.
NG >> Replace mass air flow sensor ( with intake air temperature sensor).
PBIB2625E
PBIB1565E
Voltage: Approximately 5V
PBIB1169E
Continuity should exist.
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
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EC-192
< SERVICE INFORMATION >[VQ35DE]
DTC P0112, P0113 IAT SENSOR
5.CHECK INTERMITTENT INCIDENT
Refer to EC-139
.
>> INSPECTION END
Component InspectionINFOID:0000000001326011
INTAKE AIR TEMPERATURE SENSOR
Check resistance between mass air flow sensor terminals 5 and 6 under the following conditions.
If NG, replace mass air flow sensor (with intake air temperature sen-
sor).
Removal and InstallationINFOID:0000000001326012
MASS AIR FLOW SENSOR
Refer to EM-17.
Intake air temperature °C ( °F) Resistance k Ω
25 (77) 1.800 - 2.200
PBIB1604E
SEF012P
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0127 IAT SENSOREC-207
< SERVICE INFORMATION > [VQ35DE]
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DTC P0127 IAT SENSOR
Component DescriptionINFOID:0000000001326034
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.

*: This data is reference values and is 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:0000000001326035
DTC Confirmation ProcedureINFOID:0000000001326036
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).
PBIB1604E
Intake air temperature
°C ( °F) Voltage* V Resistance k
Ω
25 (77) 3.30 1.800 - 2.200
80 (176) 1.22 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
(Intake air temperature sensor circuit is
open or shorted)
 Intake air temperature sensor
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
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EC-208
< SERVICE INFORMATION >[VQ35DE]
DTC P0127 IAT SENSOR
2. Start engine.
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-208, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001326037
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screw on the body. Refer to EC-144, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to EC-208, "
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-139
.
Refer to EC-190, "
Wiring Diagram".
>> INSPECTION END
Component InspectionINFOID:0000000001326038
INTAKE AIR TEMPERATURE SENSOR
Check resistance between intake air temperature sensor terminals 5
and 6 under the following conditions.
If NG, replace mass air flow sensor (with intake air temperature sen-
sor).
PBIB2625E
Intake air temperature °C ( °F) Resistance k Ω
25 (77) 1.800 - 2.200
PBIB1604E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0127 IAT SENSOREC-209
< SERVICE INFORMATION > [VQ35DE]
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Removal and InstallationINFOID:0000000001326039
MASS AIR FLOW SENSOR
Refer to
EM-17.
SEF012P
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EC-236
< SERVICE INFORMATION >[VQ35DE]
DTC P0133, P0153
A/F SENSOR 1
DTC P0133, P0153 A/F SENSOR 1
Component DescriptionINFOID:0000000001326067
The air fuel ratio (A/F) sensor 1 is a planar dual-cell limit current sen-
sor. The sensor element of the air fuel ratio (A/F) sensor 1 is the
combination of a Nernst concentration cell (sensor cell) with an oxy-
gen-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. Therefore, the air fuel ratio (A/F) sen-
sor 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 temperature of 700 - 800 °C (1,292 - 1,472 °F).
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001326068
Specification data are reference values.
On Board Diagn osis LogicINFOID:0000000001326069
To judge the malfunction of air fuel ratio (A/F) sensor 1, this diagnosis measures response time of the A/F sig-
nal computed by ECM from the air fuel ratio (A/F) s ensor 1 signal. The time is compensated by engine operat-
ing (speed and load), fuel feedback control constant, and the air fuel ratio (A/F) sensor 1 temperature 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:0000000001326070
NOTE:
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 1.5V
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 air fuel ratio (A/F) sensor 1 signal takes more
than the specified time.  Harness or connectors
[Air fuel ratio (A/F) sensor 1 circuit is
open or shorted.]
 Air fuel ratio (A/F) sensor 1
 Air fuel ratio (A/F) sensor 1 heater
 Fuel pressure
 Fuel injector
 Intake air leaks
 Exhaust gas leaks
PCV
 Mass air flow sensor
P0153
0153
(Bank 2)
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DTC P0133, P0153 A/F SENSOR 1
EC-237
< SERVICE INFORMATION > [VQ35DE]
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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.
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-131
.
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-131
.
10. Make sure that “OK” is display ed after touching “SELF-DIAG RESULT”.
If “NG” is displayed, go to EC-241, "
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 and make sure that no DTC is displayed. If 1st trip DTC is displayed, go to EC-241, "
Diagnosis Procedure".
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