Infiniti F50. Manual - part 406

 

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Infiniti F50. Manual - part 406

 

 

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

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DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

PFP:16600

On Board Diagnosis Logic

EBS00MCM

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 heated oxygen sensors 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 lights up the MIL (2 trip detection logic).

DTC Confirmation Procedure

EBS00MCN

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-II

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-II.

4.

Clear the self-learning control coefficient by touching “CLEAR”.

5.

Select “DATA MONITOR” mode with CONSULT-II.

6.

Start engine again and let it idle for at least 10 minutes.
The 1st trip DTC P0171 or P0174 should be detected at this
stage, if a malfunction exists. If so, go to 

EC-269, "Diagnostic

Procedure"

 .

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-269, "Diagnostic Procedure"

 . If engine does not

start, check exhaust and intake air leak visually.

Sensor

Input Signal to ECM

ECM function

Actuator

Heated oxygen sensors 1

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

Fuel injection control

Fuel injectors

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

Heated oxygen sensor 1

Injectors

Exhaust gas leaks

Incorrect fuel pressure

Lack of fuel

Mass air flow sensor

Incorrect PCV hose connection

P0174
0174
(Bank 2)

SEF968Y

EC-266

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

 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. Then
restart and run engine for at least 5 seconds at idle speed.

4.

Stop engine and reconnect mass air flow sensor harness con-
nector.

5.

Select “MODE 3” with GST. Make sure DTC P0102 is detected.

6.

Select “MODE 4” with GST and erase the DTC P0102.

7.

Start engine again and let it idle for at least 10 minutes.

8.

Select “MODE 7” with GST. The 1st trip DTC P0171 or P0174
should be detected at this stage, if a malfunction exists. If so, go
to 

EC-269, "Diagnostic Procedure"

 .

9.

If it is difficult to start engine at step 7, the fuel injection system
has a malfunction.

10. Crank engine while depressing accelerator pedal. If engine starts, go to 

EC-269, "Diagnostic Procedure"

 .

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

PBIB0012E

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

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Wiring Diagram

EBS00MCO

BANK 1

TBWM0151E

EC-268

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

BANK 2

TBWM0152E

 

 

 

 

 

 

 

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