Nissan Pathfinder (2005 year). Instruction — part 175
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-251
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EC
2005 Pathfinder
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 harness continuity between the following terminals.
Refer to Wiring Diagram.
5.
Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.
6.
Also check harness for short to power.
OK or NG
OK
>> GO TO 4.
NG
>> Repair open circuit or short to ground or short to power in harness or connectors.
A/F sensor 1 terminal
ECM terminal
Bank 1
1
16
2
75
5
35
6
56
Bank 2
1
76
2
77
5
57
6
58
Continuity should exist.
Bank 1
Bank 2
A/F sensor 1 terminal
ECM terminal
A/F sensor 1 terminal
ECM terminal
1
16
1
76
2
75
2
77
5
35
5
57
6
56
6
58
Continuity should not exist.
BBIA0544E
EC-252
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
2005 Pathfinder
4.
CHECK FUEL PRESSURE
1.
Release fuel pressure to zero. Refer to
EC-91, "FUEL PRESSURE RELEASE"
.
2.
Install fuel pressure gauge and check fuel pressure. Refer to
.
OK or NG
OK (With CONSULT-II)>>GO TO 6.
OK (Without CONSULT-II)>>GO TO 7.
NG
>> GO TO 5.
5.
DETECT MALFUNCTIONING PART
Check the following.
●
Fuel pump and circuit (Refer to
.)
●
Fuel pressure regulator (Refer to
.)
●
Fuel lines
●
Fuel filter for clogging
>> Repair or replace.
6.
CHECK MASS AIR FLOW SENSOR
With CONSULT-II
1.
Install all removed parts.
2.
Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-II.
OK or NG
OK
>> GO TO 8.
NG
>> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or
ground. Refer to
.
7.
CHECK MASS AIR FLOW SENSOR
With GST
1.
Install all removed parts.
2.
Check mass air flow sensor signal in Service $01 with GST.
OK or NG
OK (P0171)>>GO TO 9.
OK (P0174)>>GO TO 11.
NG
>> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or
ground. Refer to
.
At idling: 350 kPa (3.57 kg/cm
2
, 51 psi)
2.0 - 6.0 g·m/sec:
at idling
7.0 - 20.0 g·m/sec:
at 2,500 rpm
2.0 - 6.0 g·m/sec:
at idling
7.0 - 20.0 g·m/sec:
at 2,500 rpm
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-253
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2005 Pathfinder
8.
CHECK FUNCTION OF INJECTOR
With CONSULT-II
1.
Start engine.
2.
Perform “POWER BALANCE” in “ACTIVE TEST” mode with
CONSULT-II.
3.
Make sure that each circuit produces a momentary engine
speed drop.
OK or NG
OK
>> GO TO 12.
NG
>> Perform trouble diagnosis for INJECTOR CIRCUIT, refer to
.
PBIB0133E
EC-254
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
2005 Pathfinder
9.
CHECK FUNCTION OF INJECTOR-I
Without CONSULT-II
1.
Stop engine.
2.
Disconnect harness connector F44, F101
3.
Turn ignition switch ON.
4.
Check voltage between harness connector F44 terminal 3 and
ground with CONSULT-II or tester.
5.
Turn ignition switch OFF.
6.
Disconnect ECM harness connector.
7.
Check harness continuity between harness connector F44 and
ECM as follows.
Refer to Wiring Diagram.
8.
Also check harness for short to ground and short to power.
OK or NG
OK
>> GO TO 10.
NG
>> Perform trouble diagnosis for INJECTOR CIRCUIT, refer to
.
10.
CHECK FUNCTION OF INJECTOR-II
Provide battery voltage between harness connector F101 as follows
and then interrupt it. Listen to each injector operating sound.
OK or NG
OK
>> GO TO 12.
NG
>> Perform trouble diagnosis for INJECTOR CIRCUIT, refer to
.
BBIA0587E
Voltage: Battery voltage
Cylinder
Harness connector F44
terminal
ECM terminal
1
2
23
2
1
22
3
4
21
Continuity should exist.
PBIB2633E
Cylinder
Harness connector F101 terminal
(+)
(–)
1
3
2
2
3
1
3
3
4
Operating sound should exist.
PBIB2634E
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-255
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2005 Pathfinder
11.
CHECK FUNCTION OF INJECTOR
1.
Start engine.
2.
Listen to injectors No.2, No.4, No.6 operating sound.
OK or NG
OK
>> GO TO 12.
NG
>> Perform trouble diagnosis for INJECTOR CIRCUIT, refer
to
.
12.
CHECK INJECTOR
1.
Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
2.
Turn ignition switch OFF.
3.
Disconnect all injector harness connectors.
4.
Remove injector gallery assembly. Refer to
EM-34, "FUEL INJECTOR AND FUEL TUBE"
.
Keep fuel hose and all injectors connected to injector gallery.
5.
For DTC P0171, reconnect injector harness connectors on bank 1.
For DTC P0174, reconnect injector harness connectors on bank 2.
6.
Disconnect all ignition coil harness connectors.
7.
Prepare pans or saucers under each injector.
8.
Crank engine for about 3 seconds.
For DTC P0171, make sure that fuel sprays out from injectors
on bank 1.
For DTC P0174, make sure that fuel sprays out from injectors
on bank 2.
OK or NG
OK
>> GO TO 13.
NG
>> Replace injectors from which fuel does not spray out.
Always replace O-ring with new ones.
13.
CHECK INTERMITTENT INCIDENT
Refer to
EC-158, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"
.
>> INSPECTION END
Clicking noise should exist.
PBIB1986E
Fuel should be sprayed evenly for each injector.
PBIB1726E
EC-256
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
2005 Pathfinder
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
PFP:16600
On Board Diagnosis Logic
UBS00K7E
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 air fuel ratio (A/F) 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
UBS00K7F
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 a certain time. 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.
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.)
●
Air fuel ratio (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).
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-257
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EC
2005 Pathfinder
8.
Crank engine while depressing accelerator pedal.
If engine starts, go to
EC-260, "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 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 Service $03 with GST. Make sure DTC P0102 is
detected.
6.
Select Service $04 with GST and erase the DTC P0102.
7.
Start engine again and let it idle for at least 10 minutes.
8.
Select Service $07 with GST. The 1st trip DTC P0172 or P0175
should be detected at this stage, if a malfunction exists. If so, go
to
EC-260, "Diagnostic Procedure"
.
NOTE:
If 1st trip DTC is not detected during above procedure, performing 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 a certain
time. 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.
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-260, "Diagnostic Procedure"
. If engine does not start, remove ignition plugs and
check for fouling, etc.
BBIA0541E
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).
EC-258
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
2005 Pathfinder
Wiring Diagram
UBS00K7G
BANK 1
BBWA1741E
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