Nissan Frontier. Manual - part 532

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

EC-699

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

YES

>> GO TO 11.

NO

>> Repair or replace PCV valve. Refer to 

EM-158, "Exploded View"

.

11.

CHECK INTERMITTENT INCIDENT

Check intermittent incident. Refer to 

GI-42, "Intermittent Incident"

.

Is the inspection result normal?

YES

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

EM-147, "Exploded View"

.

NO

>> Repair or replace error-detected parts.

EC-700

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

On Board Diagnosis Logic

INFOID:0000000009481357

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 lean), the

ECM judges the condition as the fuel injection system malfunction and illuminates the MIL (2 trip detection

logic).

DTC Confirmation Procedure

INFOID:0000000009481358

NOTE:

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-

ing the next step. 
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.

 WITH CONSULT

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.

4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Start engine again and let it idle for at least 10 minutes.
6. Check 1st trip DTC.

The 1st trip DTC P0171 or P0174 should be detected at this stage, if a malfunction exists. If so, go to 

EC-

701, "Diagnosis Procedure"

.

NOTE:

If 1st trip DTC is not detected during above procedure, 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

P0171
0171
(Bank 1)

Fuel injection system 
too lean

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

large. (The mixture ratio is too lean.)

• Intake air leaks
• Air fuel ratio (A/F) sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection

P0174
0174
(Bank 2)

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

EC-701

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

7. If it is difficult to start engine at step 6, the fuel injection system has a malfunction, too.
8. Crank engine while depressing accelerator pedal. If engine starts, go to 

EC-701, "Diagnosis Procedure"

. If

engine does not start, check exhaust and intake air leak visually.

 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.
4. Restart engine and let it idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor harness con-

nector.

6. Select Service $03 with GST. Make sure DTC P0102 is

detected.

7. Select Service $04 with GST and erase the DTC P0102.
8. Start engine again and let it idle for at least 10 minutes.
9. Select Service $07 with GST. The 1st trip DTC P0171 or P0174

should be detected at this stage, if a malfunction exists. If so, go

to 

EC-701, "Diagnosis Procedure"

.

NOTE:

If 1st trip DTC is not detected during above procedure, 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.

10. If it is difficult to start engine at step 8, the fuel injection system has a malfunction.
11. Crank engine while depressing accelerator pedal. If engine starts, go to 

EC-701, "Diagnosis Procedure"

.

If engine does not start, check exhaust and intake air leak visually.

Diagnosis Procedure

INFOID:0000000009481359

1.

CHECK EXHAUST GAS LEAK

1. Start engine and run it at idle.

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).

BBIA0368E

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).

EC-702

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

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.

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.

PBIB1216E

A/F sensor 1 terminal

ECM terminal

Bank 1

1

69

2

73

Bank 2

1

77

2

81

Continuity should exist.

Bank 1

Bank 2

A/F sensor 1 terminal

ECM terminal

A/F sensor 1 terminal

ECM terminal

1

69

1

77

2

73

2

81

Continuity should not exist.

BBIA0544E