Infiniti FX35 / FX45. Manual - part 526

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

EC-865

< SERVICE INFORMATION >

[VK45DE]

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EC

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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 input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

TBWM1333E

EC-866

< SERVICE INFORMATION >

[VK45DE]

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)

Diagnosis Procedure

INFOID:0000000001326701

1.

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 2.

NG

>> Repair or replace.

2.

CHECK FOR INTAKE AIR LEAK

TER-

MI-

NAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

24

P

A/F sensor 1 heater
(Bank 2)

[Engine is running]
• Warm-up condition
• Idle speed

Approximately 5V

40
41
42
63

PU
BR
B
G

Fuel injector No. 6
Fuel injector No. 4 
Fuel injector No. 2
Fuel injector No. 8

[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)

57

G

A/F sensor 1 (Bank 2)

[Engine is running]
• Warm-up condition
• Idle speed

Approximately 2.6V

58

L

Approximately 2.3V

76

R

Approximately 3.1V

77

OR

Approximately 2.3V

PBIB1584E

PBIB0042E

PBIB0043E

PBIB1216E

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

EC-867

< SERVICE INFORMATION >

[VK45DE]

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1.

Listen for an intake air leak after the mass air flow sensor.

2.

Check PCV hose connection.

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace.

3.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 INPUT SIGNAL CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect air fuel ratio (A/F) sensor 1 harness connector.

3.

Disconnect ECM harness connector.

4.

Check harness continuity between the following terminals.
Refer to Wiring Diagram.

5.

Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.

6.

Also check harness for short to power.

OK or NG

OK

>> GO TO 4.

: Vehicle front

1.

A/F sensor 1 (Bank 2) 
harness connector

2.

A/F sensor 1 (Bank 1) 
harness connector

A/F sensor 1 terminal

ECM terminal

Bank 1

1

16

2

75

5

35

6

56

Bank 2

1

76

2

77

5

57

6

58

Continuity should exist.

Bank 1

Bank 2

A/F sensor 1 terminal

ECM terminal

A/F sensor 1 terminal

ECM terminal

1

16

1

76

2

75

2

77

5

35

5

57

6

56

6

58

Continuity should not exist.

PBIB3246E

EC-868

< SERVICE INFORMATION >

[VK45DE]

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

4.

CHECK FUEL PRESSURE

1.

Release fuel pressure to zero. Refer to 

EC-665, "Fuel Pressure Check"

.

2.

Install fuel pressure gauge and check fuel pressure. Refer to 

EC-665, "Fuel Pressure Check"

.

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-1155

.)

• Fuel pressure regulator (Refer to 

EC-665, "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 CONSULT-III)>>GO TO 8.
NG

>> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or

grounds. Refer to 

EC-768

.

7.

CHECK FUNCTION OF FUEL INJECTOR-I

 With CONSULT-III

1.

Start engine.

2.

Perform “POWER BALANCE” in “ACTIVE 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 

EC-1149

.

8.

CHECK FUNCTION OF FUEL INJECTOR-I

 Without CONSULT-III

1.

Turn ignition switch OFF.

2.

Disconnect harness connectors F21, F201 (Bank 1) and F41, F221 (Bank 2).

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