Infiniti FX35 / FX45. Manual - part 527

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

EC-869

< SERVICE INFORMATION >

[VK45DE]

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3.

Turn ignition switch ON.

4.

Check voltage between the following;
harness connector F21 terminal 5 and ground,
harness connector F41 terminal 5 and ground.

5.

Turn ignition switch OFF.

6.

Disconnect ECM harness connector.

7.

Check harness continuity between the following terminals.

8.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 9.

NG

>> Perform trouble diagnosis for 

EC-1149

.

9.

CHECK FUNCTION OF FUEL INJECTOR-II

Provide battery voltage between the following terminals, and then
interrupt it. Listen to each fuel injector operating sound.

: Vehicle front

1.

Harness connectors F41, F221

2.

Harness connectors F21, F201

Voltage: Battery voltage

Cylinder

Harness connector terminal

ECM terminal

1

F21 terminal 3

23

3

F21 terminal 2

22

5

F21 terminal 1

21

7

F21 terminal 6

44

2

F41 terminal 3

42

4

F41 terminal 2

41

6

F41 terminal 1

40

8

F41 terminal 6

63

Continuity should exist.

PBIB3248E

PBIB0180E

Cylinder

Harness connector

terminal

(+)

(–)

1

F201

5

3

3

2

5

1

7

6

PBIB2449E

EC-870

< SERVICE INFORMATION >

[VK45DE]

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

OK or NG

OK

>> GO TO 10.

NG

>> Perform trouble diagnosis for 

EC-1149

.

10.

CHECK FUEL INJECTOR

1.

Turn ignition switch OFF.

2.

Confirm that the engine is cooled down and there are no fire hazards near the vehicle.

3.

Disconnect all fuel injector harness connectors.

4.

Remove fuel tube assembly. Refer to 

EM-190

.

Keep fuel hose and all fuel injectors connected to fuel tube.

5.

For DTC P0171, reconnect fuel injector harness connectors on bank 1.
For DTC P0174, reconnect fuel injector harness connectors on bank 2.

6.

Disconnect all ignition coil harness connectors.

7.

Prepare pans or saucers under each fuel injector.

8.

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-717

.

>> INSPECTION END

2

F221

5

3

4

2

6

1

8

6

Operating sound should exist.

Cylinder

Harness connector

terminal

(+)

(–)

Fuel should be sprayed evenly for each fuel injector.

PBIB1726E

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

EC-871

< SERVICE INFORMATION >

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DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

On Board Diagnosis Logic

INFOID:0000000001326702

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 correct the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extremely 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 Procedure

INFOID:0000000001326703

NOTE:
If DTC Confirmation Procedure has been previously conducted, 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-LEARNING 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 

EC-866, "Diagnosis Procedure"

.

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-866, "Diagnosis Procedure"

.

If 1st trip DTC is not detected, performing 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 Data means the vehicle operation that the following con-
ditions should be satisfied at the same time.

Sensor

Input Signal to ECM

ECM function

Actuator

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.)

• 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)

EC-872

< SERVICE INFORMATION >

[VK45DE]

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

9.

Check 1st trip DTC.

10. The 1st trip is detected, go to 

EC-866, "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 (1) 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-866, "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-866, "Diagnosis Procedure"

.

If 1st trip DTC is not detected, performing 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 Data 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-866, "Diagnosis Procedure"

.

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).

PBIB3230E

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).