Infiniti M35/M45 Y50. Manual - part 640
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
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DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
PFP:16600
On Board Diagnosis Logic
NBS005FD
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
NBS005FE
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 P0172, P0175 should be detected at this stage,
if a malfunction exists. If so, go to
.
NOTE:
If 1st trip DTC is not detected during above procedure, perform-
ing the following procedure is advised.
a.
Turn ignition switch OFF and wait at least 10 seconds.
b.
Start engine and drive the vehicle under the similar conditions to
(1st trip) Freeze Frame Data for 10 minutes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con-
ditions should be satisfied at the same time.
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.
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
DTC detecting condition
Possible cause
P0172
0172
(Bank 1)
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
P0175
0175
(Bank 2)
SEF968Y
Engine speed
Engine speed in the freeze frame data
±
400 rpm
Vehicle speed
Vehicle speed in the freeze frame data
±
10 km/h (6 MPH)
Engine coolant temperature
(T) condition
When the freeze frame data shows lower than 70
°
C (158
°
F),
T should be lower than 70
°
C (158
°
F).
When the freeze frame data shows higher than or equal to 70
°
C (158
°
F),
T should be higher than or equal to 70
°
C (158
°
F).