Nissan Frontier D22. Manual - part 282

DTC P0171 FUEL INJECTION SYSTEM FUNCTION

EC-231

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EC

Component Inspection

UBS00D54

MASS AIR FLOW SENSOR

 With CONSULT-II

1.

Start engine and warm it up to normal operating temperature.

2.

Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-II.

 With GST

1.

Start engine and warm it up to normal operating temperature.

2.

Check mass air flow sensor signal in MODE 1 with GST.

INJECTOR

1.

Disconnect all ignition coil harness connectors.

2.

Place pans or saucers under each injector.

3.

Crank engine for about 3 seconds. Make sure that fuel sprays
out from injectors.
Fuel should be sprayed evenly for each cylinder.

at idling

: 0.9 - 5.8 g·m/sec

at 2,500 rpm

: 7.5 - 13.2 g·m/sec

at idling

: 0.9 - 5.8 g·m/sec

at 2,500 rpm

: 7.5 - 13.2 g·m/sec

SEF595Q

EC-232

[KA24DE]

DTC P0172 FUEL INJECTION SYSTEM FUNCTION

DTC P0172 FUEL INJECTION SYSTEM FUNCTION

PFP:16600

On Board Diagnosis Logic

UBS00D55

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

DTC Confirmation Procedure

UBS00D56

NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch OFF and wait at
least 5 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 5 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 P0172 should be detected at this stage, if a
malfunction exists. If so, go to 

EC-235, "Diagnostic Procedure"

 .

7.

If it is difficult to start engine at step 6, the fuel injection system
has a malfunction.

8.

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

EC-235, "Diagnostic Procedure"

 . If engine does not

start, remove ignition plugs and check for fouling, etc.

 WITH GST

1.

Start engine and warm it up to normal operating temperature.

2.

Turn ignition switch OFF and wait at least 5 seconds.

Sensor

Input Signal to ECM

ECM function

Actuator

Heated oxygen sensor 1

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

Fuel injection & mixture 
ratio control

Fuel injector

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0172

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.)

●

Heated oxygen sensor 1

●

Fuel injector

●

Exhaust gas leaks

●

Incorrect fuel pressure

●

Mass air flow sensor

SEF215Z

SEF058Y

DTC P0172 FUEL INJECTION SYSTEM FUNCTION

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EC

3.

Disconnect mass air flow sensor harness connector. Then
restart and run engine for at least 3 seconds at idle speed.

4.

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

5.

Select “MODE 7” with GST. Make sure DTC P0102 is detected.

6.

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

7.

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

8.

Select “MODE 7” with GST. The 1st trip DTC P0172 should be
detected at this stage, if a malfunction exists. If so, go to 

EC-

235, "Diagnostic Procedure"

 .

9.

If it is difficult to start engine at step 8, the fuel injection system has a malfunction.

10. Crank engine while depressing accelerator pedal.

If engine starts, go to 

EC-235, "Diagnostic Procedure"

 . If engine does not start, remove ignition plugs and

check for fouling, etc.

AEC131A

EC-234

[KA24DE]

DTC P0172 FUEL INJECTION SYSTEM FUNCTION

Wiring Diagram

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