Nissan Juke F15. Manual - part 524

P0172 FUEL INJECTION SYSTEM FUNCTION

EC-909

< DTC/CIRCUIT DIAGNOSIS >

[MR EXCEPT FOR NISMO RS MODELS]

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P0172 FUEL INJECTION SYSTEM FUNCTION

DTC Logic

INFOID:0000000012198406

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 the A/F sensors 1. The ECM calcu-

lates 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 rich.), the

ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting 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-762, "Description"

.

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

>> Proceed to 

EC-910, "Diagnosis Procedure"

.

NO

>> Check exhaust and intake air leak visually.

4.

PERFORM DTC CONFIRMATION PROCEDURE-II

1. Start engine and let it idle for at least 5 minutes.

2. Check 1st trip DTC.
Is 1st trip DTC detected?

YES

>> Proceed to 

EC-910, "Diagnosis Procedure"

.

NO

>> GO TO 5.

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

(Trouble diagnosis con-

tent)

DTC detecting condition 

Possible cause

P0172

FUEL SYS-RICH-B1
(Fuel injection system too 
rich)

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

large. (The mixture ratio is too rich.)

• A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Mass air flow sensor

EC-910

< DTC/CIRCUIT DIAGNOSIS >

[MR EXCEPT FOR NISMO RS MODELS]

P0172 FUEL INJECTION SYSTEM FUNCTION

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

>> Proceed to 

EC-910, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000012198407

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).

Is exhaust gas leak detected?

YES

>> Repair or replace error-detected parts.

NO

>> GO TO 2.

2.

CHECK FOR INTAKE AIR LEAK

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

YES

>> Repair or replace error-detected parts.

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.

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

and ground.

VHCL SPEED SE

50 - 120 km/h (31 - 75 MPH)

PBIB1216E

+

−

Continuity

A/F sensor 1

ECM

Connector

Terminal

Connector

Terminal

F72

1

F24

79

Existed

2

74

P0172 FUEL INJECTION SYSTEM FUNCTION

EC-911

< DTC/CIRCUIT DIAGNOSIS >

[MR EXCEPT FOR NISMO RS MODELS]

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

YES

>> GO TO 4.

NO

>> Repair or replace error-detected parts.

4.

CHECK FUEL PRESSURE

Check fuel pressure. Refer to 

EC-771, "Work Procedure"

.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> GO TO 5.

5.

 DETECT MALFUNCTIONING PART

Check fuel hoses and fuel tubes for clogging. Refer to 

EM-203, "Exploded View"

.

Is the inspection result normal?

YES

>> Replace “fuel filter and fuel pump assembly”. Refer to 

FL-6, "2WD : Exploded View"

 (2WD) or 

FL-

10, "AWD : Exploded View"

 (AWD).

NO

>> Repair or replace error-detected parts.

6.

CHECK MASS AIR FLOW SENSOR

With CONSULT

1. Turn ignition switch OFF.

2. Reconnect all harness connectors disconnected.

3. Start engine and warm it up to normal operating temperature.

4. Connect CONSULT and select “DATA MONITOR” mode.

5. Select “MASS AIR FLOW SENSOR (Hz)” and check the indication.

*: Check for linear frequency rise in response to engine being increased to about 4,000 rpm.

Without CONSULT

1. Turn ignition switch OFF.

2. Reconnect all harness connectors disconnected.

3. Start engine and warm it up to normal operating temperature.

4. Check the frequency between ECM harness connector terminals under the following conditions.

+

−

Continuity

A/F sensor 1

Connector

Terminal

F72

1

Ground

Not existed

2

+

−

Continuity

ECM

Connector

Terminal

F24

79

Ground

Not existed

74

Monitor item

Condition

Indication (Hz)

MASS AIR FLOW SENSOR (Hz)

Ignition switch ON (Engine stopped.)

Approx. 3,700 Hz

Idle (Engine is warmed-up to normal operating temperature.)

5,100 – 5,500 Hz

2,500 rpm (Engine is warmed-up to normal operating temper-
ature.)

6,100 – 6,500 Hz

Idle to about 4,000 rpm

5,100 – 5,500 to Approx. 7,000 Hz*

EC-912

< DTC/CIRCUIT DIAGNOSIS >

[MR EXCEPT FOR NISMO RS MODELS]

P0172 FUEL INJECTION SYSTEM FUNCTION

*: Check for linear frequency rise in response to engine being increased to about 4,000 rpm.

Is the inspection result normal?

YES

>> GO TO 7.

NO

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

grounds. Refer to 

EC-843, "DTC Logic"

.

7.

CHECK FUNCTION OF FUEL INJECTOR

With CONSULT

1. Start engine.

2. Perform “POWER BALANCE” in “ACTIVE TEST” mode of “ENGINE” using CONSULT.

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

Without CONSULT

1. Let engine idle.

2. Listen to each fuel injector operating sound.

Is the inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-45, "Intermittent

Incident"

.

NO

>> Perform trouble diagnosis for “FUEL INJECTOR”, refer

to 

EC-1204, "Component Function Check"

.

ECM

Condition

Frequency (Hz)

Connector

+

–

Terminal

F23

37

42

Ignition switch ON (Engine stopped.)

Approx. 3,700 Hz

Idle (Engine is warmed-up to normal operating 
temperature.)

5,100 – 5,500 Hz

2,500 rpm (Engine is warmed-up to normal op-
erating temperature.)

6,100 – 6,500 Hz

Idle to about 4,000 rpm

5,100 – 5,500 to Approx. 7,000 Hz*

Clicking noise should be heard.

PBIB3332E