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![INFINITI FX35 2008 Service Manual
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-281
< SERVICE INFORMATION > [VQ35DE]
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OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the f INFINITI FX35 2008 Service Manual
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-281
< SERVICE INFORMATION > [VQ35DE]
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OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the f](/manual-img/42/57017/w960_57017-1520.png)
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-281
< SERVICE INFORMATION > [VQ35DE]
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OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
Fuel pump and circuit (Refer to EC-558
.)
Fuel pressure regulator (Refer to EC-87, "
Fuel Pressure Check")
Fuel lines (Refer to FL-3, "
Checking Fuel Line".)
Fuel filter for clogging
>> Repair or replace.
6.CHECK MASS AIR FLOW SENSOR
With CONSULT-III
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
OK or NG
OK (With CONSULT-III)>>GO TO 7.
OK (Without COUSULT-II)>>GO TO 8.
NG >> Check connectors for rusted terminals or loose c onnections in the mass air flow sensor circuit or
ground. Refer to EC-175
.
7.CHECK FUNCTION OF FUEL INJECTOR
With CONSULT-III
1. Start engine.
2. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-III.
3. Make sure that each circuit produces a momentary engine speed drop.
OK or NG
OK >> GO TO 10.
NG >> Perform trouble diagnosis for FUEL INJECTOR, refer to EC-552
.
8.CHECK FUNCTION OF FUEL INJECTOR-I
Without CONSULT-III
1. Turn ignition switch OFF. At idling: Approximately 350 kPa (3.57 kg/cm
2, 51 psi)
2.0 - 6.0 g·m/sec: at idling
7.0 - 20.0 g·m/sec: at 2,500 rpm
2.0 - 6.0 g·m/sec: at idling
7.0 - 20.0 g·m/sec: at 2,500 rpm
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![INFINITI FX35 2008 Service Manual
EC-282
< SERVICE INFORMATION >[VQ35DE]
DTC P0171, P0174 FUEL IN
JECTION SYSTEM FUNCTION
2. Disconnect harness connectors F50, F251
3. Turn ignition switch ON.
4. Check voltage between harness connect INFINITI FX35 2008 Service Manual
EC-282
< SERVICE INFORMATION >[VQ35DE]
DTC P0171, P0174 FUEL IN
JECTION SYSTEM FUNCTION
2. Disconnect harness connectors F50, F251
3. Turn ignition switch ON.
4. Check voltage between harness connect](/manual-img/42/57017/w960_57017-1521.png)
EC-282
< SERVICE INFORMATION >[VQ35DE]
DTC P0171, P0174 FUEL IN
JECTION SYSTEM FUNCTION
2. Disconnect harness connectors F50, F251
3. Turn ignition switch ON.
4. Check voltage between harness connector F50 terminal 5 and
ground.
5. Turn ignition switch OFF.
6. Disconnect ECM harness connector.
7. Check harness continuity between harness connector F50 and ECM as follows.
Refer to Wiring Diagram.
8. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 9.
NG >> Perform trouble diagnosis for FUEL INJECTOR, refer to EC-552
.
9.CHECK FUNCTION OF FUEL INJECTOR-II
Provide battery voltage between harness connector F251 as follows
and then interrupt it. Listen to each fuel injector operating sound.
OK or NG
PBIB2624E
Voltage: Battery voltage
Cylinder Harness connector F50
terminal ECM terminal
1623
2442
3222
4341
5121
6740
Continuity should exist.
PBIB2323E
Cylinder Harness connector F251 terminal
(+) (–)
1
56
24
32
43
51
67
Operating sound should exist.
PBIB2497E
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Page 1523 of 3924
![INFINITI FX35 2008 Service Manual
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-283
< SERVICE INFORMATION > [VQ35DE]
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OK >> GO TO 10.
NG >> Perform trouble diagnosis for FUEL INJECTOR, refer to
EC INFINITI FX35 2008 Service Manual
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-283
< SERVICE INFORMATION > [VQ35DE]
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OK >> GO TO 10.
NG >> Perform trouble diagnosis for FUEL INJECTOR, refer to
EC](/manual-img/42/57017/w960_57017-1522.png)
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-283
< SERVICE INFORMATION > [VQ35DE]
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OK >> GO TO 10.
NG >> Perform trouble diagnosis for FUEL INJECTOR, refer to
EC-552
.
10.CHECK FUEL INJECTOR
1. Confirm that the engine is cooled down and t here are no fire hazards near the vehicle.
2. Turn ignition switch OFF.
3. Reconnect all harness connectors disconnected.
4. Disconnect all fuel injector harness connectors.
5. Remove fuel injector gallery assembly. Refer to EM-45
.
Keep fuel hose and all fuel injectors connected to fuel injector gallery.
6. For DTC P0171, reconnect fuel in jector harness connectors on bank 1.
For DTC P0174, reconnect fuel inje ctor harness connectors on bank 2.
7. Disconnect all ignition coil harness connectors.
8. Prepare pans or saucers under each fuel injector.
9. Crank engine for about 3 seconds. For DTC P0171, make sure that fuel sprays out from fuel injec-
tors on bank 1.
For DTC P0174, make sure that fuel sprays out from fuel injec-
tors on bank 2.
OK or NG
OK >> GO TO 11.
NG >> Replace fuel injectors from which fuel does not spray out. Always replace O-ring with new ones.
11 .CHECK INTERMITTENT INCIDENT
Refer to EC-139
.
>> INSPECTION END
Fuel should be sprayed evenly
for each fuel injector.
PBIB1726E
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Page 1524 of 3924
![INFINITI FX35 2008 Service Manual
EC-284
< SERVICE INFORMATION >[VQ35DE]
DTC P0172, P0175 FUEL IN
JECTION SYSTEM FUNCTION
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000001326105
With the Air-Fu INFINITI FX35 2008 Service Manual
EC-284
< SERVICE INFORMATION >[VQ35DE]
DTC P0172, P0175 FUEL IN
JECTION SYSTEM FUNCTION
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000001326105
With the Air-Fu](/manual-img/42/57017/w960_57017-1523.png)
EC-284
< SERVICE INFORMATION >[VQ35DE]
DTC P0172, P0175 FUEL IN
JECTION SYSTEM FUNCTION
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000001326105
With the Air-Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the air fuel ratio (A/F) sensor 1. The
ECM calculates the necessary compensation to corr ect the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extrem ely large (the actual mixture ratio is too rich.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureINFOID:0000000001609264
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.
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. Turn ignition switch ON and select “SELF-LE ARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-III.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Start engine. If it is difficult to start engine, the fuel injection system has a malfunction.
Perform the following procedure is advised.
a. Crank engine while depressing accelerator pedal.
b. If engine starts, go to . If engine does not start, remove ignition plugs and check for fouling, etc.
6. Keep engine at idle for at least 10 minutes.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-289, "
Diagnosis Procedure".
If 1st trip DTC is not detected, per forming the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for 10 min- utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Sensor Input signal to ECM ECM function Actuator
Air fuel ration (A/F) sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal) Fuel injection
control
Fuel injector
DTC No.
Trouble diagnosis
name DTC detecting condition Possible cause
P0172
0172
(Bank 1) Fuel injection system
too rich Fuel injection system does not operate properly.
The amount of mixture ratio compensation is too
large. (The mixture ratio is too rich.) Air fuel ratio (A/F) sensor 1
Fuel injector
Exhaust gas leaks
Incorrect fuel pressure
Mass air flow sensor
P0175
0175
(Bank 2)
Engine speed Engine speed in the freeze frame data
± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
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Page 1525 of 3924
![INFINITI FX35 2008 Service Manual
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-285
< SERVICE INFORMATION > [VQ35DE]
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10. The 1st trip is detected, go to
EC-289, "
Diagnosis INFINITI FX35 2008 Service Manual
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-285
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O9. Check 1st trip DTC.
10. The 1st trip is detected, go to
EC-289, "
Diagnosis](/manual-img/42/57017/w960_57017-1524.png)
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-285
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O9. Check 1st trip DTC.
10. The 1st trip is detected, go to
EC-289, "
Diagnosis Procedure".
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Disconnect mass air flow sensor harness connector. Then
restart and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con- nector.
5. Select Service $03 with GST. Make sure DTC P0102 is detected.
6. Select Service $04 with GST and erase the DTC P0102.
7. Start engine. If it is difficult to start engine, the fuel injection system has a mal-
function.
Perform the following procedure is advised.
a. Crank engine while depressing accelerator pedal.
b. If engine starts, go to EC-289, "
Diagnosis Procedure".
If engine does not start, remove ignition plugs and check for fouling, etc.
8. Keep engine at idle for at least 10 minutes.
9. Check 1st trip DTC.
10. If 1st trip DTC is detected, go to EC-289, "
Diagnosis Procedure".
If 1st trip DTC is not detected, per forming the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar condi tions to (1st trip) Freeze Frame Data for 10 min-
utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
11. Check 1st trip DTC.
12. The 1st trip is detected, go to EC-289, "
Diagnosis Procedure".
Engine coolant temperature (T)
conditionWhen the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
PBIB1565E
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
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EC-286
< SERVICE INFORMATION >[VQ35DE]
DTC P0172, P0175 FUEL IN
JECTION SYSTEM FUNCTION
Wiring Diagram
INFOID:0000000001326107
BANK 1
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-III.
CAUTION:
TBWM1594E
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![INFINITI FX35 2008 Service Manual
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-287
< SERVICE INFORMATION > [VQ35DE]
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Do not use ECM ground terminals wh
en measuring input/output voltage. Doing so INFINITI FX35 2008 Service Manual
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-287
< SERVICE INFORMATION > [VQ35DE]
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Do not use ECM ground terminals wh
en measuring input/output voltage. Doing so](/manual-img/42/57017/w960_57017-1526.png)
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-287
< SERVICE INFORMATION > [VQ35DE]
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Do not use ECM ground terminals wh
en measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)TER-
MI-
NAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
2R/L A/F sensor 1 heater
(bank 1) [Engine is running]
Warm-up condition
Idle speed Approximately 5V
16 G A/F sensor 1 (bank 1) [Engine is running]
Warm-up condition
Idle speed Approximately 3.1V
35 B/R Approximately 2.6V
56 L Approximately 2.3V
75 R/B Approximately 2.3V
21
22
23 W
G
R Fuel injector No. 5
Fuel injector No. 3
Fuel injector No. 1 [Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Warm-up condition
Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
PBIB1584E
SEC984C
SEC985C
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EC-288
< SERVICE INFORMATION >[VQ35DE]
DTC P0172, P0175 FUEL IN
JECTION SYSTEM FUNCTION
BANK 2
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-III.
CAUTION:
Do not use ECM ground terminals when measuring in put/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
TBWM1595E
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