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Nissan Frontier. Manual - part 414

P014C, P014D, P015A, P015B, A/F SENSOR 1

EC-227

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

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

5. Also check harness for short to power.
Is the inspection result normal?

YES

>> GO TO 9.

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

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

Check A/F sensor 1 heater. Refer to

EC-157, "Component Inspection"

Is the inspection result normal?

YES

>> GO TO 10.

>> GO TO 13.

10.

CHECK MASS AIR FLOW SENSOR

Check mass air flow sensor. Refer to

EC-170, "Component Inspection"

Is the inspection result normal?

YES

>> GO TO 11.

>> Replace mass air flow sensor. Refer to

EM-27, "Removal and Installation"

11.

CHECK PCV VALVE

Check PCV valve. Refer to

EC-456, "Component Inspection"

Is the inspection result normal?

YES

>> GO TO 12.

>> Repair or replace PCV valve. Refer to

EM-37, "Exploded View"

12.

CHECK INTERMITTENT INCIDENT

Perform intermittent incident. Refer to

GI-42, "Intermittent Incident"

Is the inspection result normal?

YES

>> GO TO 13.

>> Repair or replace.

13.

REPLACE AIR FUEL RATIO (A/F) SENSOR 1

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

EM-31, "Removal and Installation"

CAUTION:

• Discard any 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 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

A/F sensor 1

ECM

Continuity

Connector

Terminal

Connector

Terminal

F65

F56

Existed

A/F sensor 1

ECM

Ground

Continuity

Connector

Terminal

Connector

Terminal

F65

F56

Ground

Not existed

EC-228

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

P0171 FUEL INJECTION SYSTEM FUNCTION

P0171 FUEL INJECTION SYSTEM FUNCTION

On Board Diagnosis Logic

INFOID:0000000009480886

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

INFOID:0000000009480887

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

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.

If it is difficult to start engine, the fuel injection system has a malfunction.

Performing the following procedure is advised.

a. 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.

b. If engine starts, go to

EC-229, "Diagnosis Procedure"

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

6. Keep engine at idle for at least 5 minutes.
7. Check 1st trip DTC.
8. The 1st trip DTC P0171 should be detected at this stage, if a malfunction exists. If so, go to

EC-229,

"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.
c.

Maintain the following conditions for at least 10 consecutive minutes.

Sensor

Input Signal to ECM

ECM

function

Actuator

Air fuel ratio (A/F) sensor 1

Density of oxygen in exhaust gas
(Mixture ratio feedback signal)

Fuel injec-
tion control

Fuel injector

DTC No.

Trouble diagnosis

name

DTC detecting condition

Possible cause

P0171
0171

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

P0171 FUEL INJECTION SYSTEM FUNCTION

EC-229

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

Hold the accelerator pedal as steady as possible.

CAUTION:

Always drive vehicle at a safe speed.

d. Check 1st trip DTC.
e. If 1st trip DTC is detected, go to

EC-229, "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 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. Check that DTC P0102 is

detected.

7. Select Service $04 with GST and erase the DTC P0102.
8. Start engine.

If it is difficult to start engine, the fuel injection system has a mal-

function.

Performing the following procedure is advised.

a. 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.

b. If engine starts, go to

EC-229, "Diagnosis Procedure"

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

9. Keep engine at idle for at least 5 minutes.
10. Check 1st trip DTC.
11. The 1st trip DTC P0171 should be detected at this stage, if a malfunction exists. If so, go to

EC-229,

"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.
c. 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.

d. Check 1st trip DTC.
e. If 1st trip DTC is detected, go to

EC-229, "Diagnosis Procedure"

Diagnosis Procedure

INFOID:0000000009480888

CHECK EXHAUST GAS LEAK

1. Start engine and run it at idle.

VHCL SPEED SE

50 - 120 km/h (31 - 75 MPH)

VHCL SPEED SE

50 - 120 km/h (31 - 75 MPH)

BBIA0622E

EC-230

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

P0171 FUEL INJECTION SYSTEM FUNCTION

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

OK or NG

>> GO TO 2.

>> Repair or replace.

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

>> GO TO 3.

>> Repair or replace.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect A/F sensor 1 harness connector and ECM harness

connector.

3. Check harness continuity between ECM terminals and A/F sen-

sor 1 terminals as follows.

Refer to Wiring Diagram.

4. Check harness continuity between ECM terminals 45, 49 and ground, or A/F sensor 1 terminals 1, 2 and

ground.

Refer to Wiring Diagram.

5. Also check harness for short to power.
OK or NG

>> GO TO 4.

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

CHECK FUEL PRESSURE

1. Release fuel pressure to zero. Refer to

EC-466, "Fuel Pressure Check"

2. Install fuel pressure gauge kit [SST (J-44321)] and check fuel pressure. Refer to

EC-466, "Fuel Pressure

Check"

OK or NG

>> GO TO 6.

>> GO TO 5.

DETECT MALFUNCTIONING PART

PBIB1216E

A/F sensor 1

ECM terminal

Continuity should exist.

Continuity should not exist.

BBIA0617E

At idling: Approximately 350 kPa (3.57 kg/cm

, 51 psi)

Content .. 412 413 414 415 ..