Nissan Pathfinder (2006 year). Manual - part 181

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

EC-307

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2006 Pathfinder

Wiring Diagram

UBS00K7C

BANK 1

BBWA2368E

EC-308

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

2006 Pathfinder

Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECMs transistor. Use a ground other than ECM terminals, such as the ground.

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

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

2

G

A/F sensor 1 heater
(Bank 1)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 5V

16

BR

A/F sensor 1 (Bank 1)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 3.1V

35

O

Approximately 2.6V

56

LG

Approximately 2.3V

75

P

Approximately 2.3V

21
22
23

W
LG
SB

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

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

EC-309

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2006 Pathfinder

BANK 2

BBWA2369E

EC-310

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

2006 Pathfinder

Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECMs transistor. Use a ground other than ECM terminals, such as the ground.

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

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

24

G

A/F sensor 1 heater
 (Bank 2)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 5V

40
41
42

V
R
O

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

[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

GR

A/F sensor 1 (Bank 2)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 2.6V

58

O

Approximately 2.3V

76

V

Approximately 3.1V

77

Y

Approximately 2.3V

PBIB1584E

SEC984C

SEC985C

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

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2006 Pathfinder

Diagnostic Procedure

UBS00K7D

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

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.

PBIB1216E

EC-312

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

2006 Pathfinder

3. 

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect corresponding A/F sensor 1 harness connector.

3.

Disconnect ECM harness connector.

4.

Check harness continuity between A/F sensor 1 terminal and ECM terminal as follows.
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.

NG

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

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.

BBIA0544E

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

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2006 Pathfinder

4. 

CHECK FUEL PRESSURE

1.

Release fuel pressure to zero. Refer to 

EC-79, "FUEL PRESSURE RELEASE"

 .

2.

Install fuel pressure gauge and check fuel pressure. Refer to 

EC-80, "FUEL PRESSURE CHECK"

 .

OK or NG

OK (With CONSULT-II)>>GO TO 6.
OK (Without CONSULT-II)>>GO TO 7.
NG

>> GO TO 5.

5. 

DETECT MALFUNCTIONING PART

Check the following.

●

Fuel pump and circuit (Refer to 

EC-640, "FUEL PUMP"

 .)

●

Fuel pressure regulator (Refer to 

EC-80, "FUEL PRESSURE CHECK"

 .)

●

Fuel lines

●

Fuel filter for clogging

>> Repair or replace.

6. 

CHECK MASS AIR FLOW SENSOR

 With CONSULT-II

1.

Install all removed parts.

2.

Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-II.

OK or NG

OK

>> GO TO 8.

NG

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

ground. Refer to 

EC-186

 .

7. 

CHECK MASS AIR FLOW SENSOR

 With GST

1.

Install all removed parts.

2.

Check mass air flow sensor signal in Service $01 with GST.

OK or NG

OK (P0171)>>GO TO 9.
OK (P0174)>>GO TO 11.
NG

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

ground. Refer to 

EC-186

 .

At idling: 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

EC-314

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

2006 Pathfinder

8. 

CHECK FUNCTION OF FUEL INJECTOR

 With CONSULT-II

1.

Start engine.

2.

Perform “POWER BALANCE” in “ACTIVE TEST” mode with
CONSULT-II.

3.

Make sure that each circuit produces a momentary engine
speed drop.

OK or NG

OK

>> GO TO 12.

NG

>> Perform trouble diagnosis for FUEL INJECTOR, refer to 

EC-633

 .

PBIB0133E