Nissan Murano. Manual - part 532

EC-238

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

P014C, P014D, P014E, P014F, P015A, P015B, P015C, P015D A/F SENSOR 1

>> Repair or replace harness or connectors.

8.

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

4.

Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector
and ground.

5.

Also check harness for short to power.

Is the inspection result normal?

YES

>> GO TO 9.

NO

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

9.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER

Refer to 

EC-160, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 10.

NO

>> GO TO 13.

10.

CHECK MASS AIR FLOW SENSOR

Check both mass air flow sensor (bank 1 and bank 2).
Refer to 

EC-169, "Component Inspection"

.

DTC

A/F sensor 1

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

• P014C
• P014D
• P015A
• P015B

1

F27

1

F8

45

Existed

2

49

• P014E
• P014F
• P015C
• P015D

2

F64

1

53

2

57

DTC

A/F sensor 1

Ground

Continuity

Bank

Connector

Terminal

• P014C
• P014D
• P015A
• P015B

1

F27

1

Ground

Not existed

2

• P014E
• P014F
• P015C
• P015D

2

F64

1

2

DTC

ECM

Ground

Continuity

Bank

Connector

Terminal

• P014C
• P014D
• P015A
• P015B

1

F8

45

Ground

Not existed

49

• P014E
• P014F
• P015C
• P015D

2

53

57

P014C, P014D, P014E, P014F, P015A, P015B, P015C, P015D A/F SENSOR 1

EC-239

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is the inspection result normal?

YES

>> GO TO 11. 

NO

>> Replace malfunctioning mass air flow sensor. Refer to 

EM-31, "Exploded View"

.

11.

CHECK PCV VALVE

Refer to 

EC-464, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 12.

NO

>> Repair or replace PCV valve. Refer to 

EM-54, "Exploded View"

.

12.

CHECK INTERMITTENT INCIDENT

Perform 

GI-44, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> GO TO 13.

NO

>> Repair or replace.

13.

REPLACE AIR FUEL RATIO (A/F) SENSOR 1

Replace malfunctioning air fuel ratio (A/F) sensor 1. Refer to 

EM-38, "Exploded View"

.

CAUTION:

• Discard any A/F sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a

hard surface such as a concrete floor; use a new one.

• Before installing new A/F sensor, clean exhaust system threads using Oxygen Sensor Thread

Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved Anti-seize Lubricant
(commercial service tool).

>> INSPECTION END

EC-240

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

DTC Logic

INFOID:0000000009719973

DTC DETECTION LOGIC

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 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 lean), the
ECM judges the condition as the fuel injection system malfunction and illuminates the MIL (2 trip detection
logic).

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing the next test.
1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON.

3.

Turn ignition switch OFF and wait at least 10 seconds.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE-I

1.

Clear the mixture ratio self-learning value. Refer to 

EC-22, "MIXTURE RATIO SELF-LEARNING VALUE

CLEAR : Special Repair Requirement"

.

2.

Start engine.

Is it difficult to start engine?

YES

>> GO TO 3.

NO

>> GO TO 4.

3.

RESTART ENGINE

If it is difficult to start engine, the fuel injection system has a malfunction, too.
Crank engine while depressing accelerator pedal.
NOTE:
• When depressing accelerator pedal three-fourths (3/4) or more, the control system does not start the

engine. Do not depress accelerator pedal too much.

Does engine start?

YES

>> Go to 

EC-241, "Diagnosis Procedure"

.

NO

>> Check exhaust and intake air leakage visually.

4.

PERFORM DTC CONFIRMATION PROCEDURE-II

1.

Keep engine idle for at least 5 minutes.

2.

Check 1st trip DTC.

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

P0171

Fuel injection system too 
lean (bank 1)

• Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too 

large. (The mixture ratio is too lean.)

• Intake air leakage
• A/F sensor 1
• Fuel injector
• Exhaust gas leakage
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection

P0174

Fuel injection system too 
lean (bank 2)

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

EC-241

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is 1st trip DTC detected?

YES

>> Go to 

EC-241, "Diagnosis Procedure"

.

NO

>> GO TO 5.

5.

PERFORM DTC CONFIRMATION PROCEDURE-III

1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Start engine.

3.

Maintain the following conditions for at least 10 consecutive minutes.
Hold the accelerator pedal as steady as possible.

CAUTION:

Always drive vehicle at a safe speed.

4.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-241, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000009719974

1.

CHECK EXHAUST GAS LEAKAGE

1.

Start engine and run it at idle.

2.

Listen for an exhaust gas leakage before three way catalyst (manifold).

Is exhaust gas leakage detected?

YES

>> Repair or replace malfunctioning part.

NO

>> GO TO 2.

2.

CHECK FOR INTAKE AIR LEAKAGE

1.

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

2.

Check PCV hose connection.

Is intake air leakage detected?

YES

>> Repair or replace malfunctioning part.

NO

>> GO TO 3.

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 the continuity between A/F sensor 1 harness connector and ECM harness connector.

VHCL SPEED SE

50 - 120 km/h (31 - 75 mph)

PBIB1216E

DTC

A/F sensor 1

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0171

1

F27

1

F8

45

Existed

2

49

P0174

2

F64

1

53

2

57