Nissan Frontier D22. Manual - part 581
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-1427
[VG33ER]
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DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
PFP:16600
On Board Diagnosis Logic
UBS00DVZ
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
UBS00DW0
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 P0171 or P0174 should be detected at this
stage, if a malfunction exists. If so, go to
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-1431, "Diagnostic Procedure"
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 5 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 connector.
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.
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
(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
●
Fuel injector
●
Exhaust gas leaks
●
Incorrect fuel pressure
●
Lack of fuel
●
Mass air flow sensor
●
Incorrect PCV hose connection
P0174
(Bank 2)
SEF968Y