Nissan Frontier D22. Manual — part 582
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-1431
[VG33ER]
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Diagnostic Procedure
UBS00DW2
1.
CHECK EXHAUST AIR LEAK
1.
Start engine and run it at idle.
2.
Listen for an exhaust air leak before three way catalyst (manifold).
OK or NG
OK
>> GO TO 2.
NG
>> Repair or replace.
2.
CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK
>> GO TO 3.
NG
>> Repair or replace.
3.
CHECK FOR PCV HOSE
Check PCV hose for loose connection or disconnection.
OK or NG
OK
>> GO TO 4.
NG
>> Repair or replace.
SEC502D
EC-1432
[VG33ER]
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
4.
CHECK HEATED OXYGEN SENSOR 1 CIRCUIT FOR OPEN AND SHORT
1.
Turn ignition switch OFF.
2.
Disconnect corresponding heated oxygen sensor 1 harness connector.
3.
Disconnect ECM harness connector.
4.
Check harness continuity between ECM terminal and HO2S1 terminal as follows.
Refer to Wiring Diagram.
5.
Check harness continuity between ECM terminal or HO2S1 terminal and ground as follows.
Refer to Wiring Diagram.
6.
Also check harness for short to power.
OK or NG
OK
>> GO TO 5.
NG
>> Repair open circuit or short to ground or short to power in harness or connectors.
5.
CHECK FUEL PRESSURE
1.
Release fuel pressure to zero.
Refer to
EC-1218, "FUEL PRESSURE RELEASE"
2.
Install fuel pressure gauge and check fuel pressure. Refer to
EC-1218, "FUEL PRESSURE CHECK"
OK or NG
OK
>> GO TO 7.
NG
>> GO TO 6.
6.
DETECT MALFUNCTIONING PART
Check the following.
●
Fuel pump and circuit (Refer to
●
Fuel pressure regulator (Refer to
.)
●
.)
●
Fuel filter for clogging
>> Repair or replace.
DTC
Terminals
Bank
ECM
Sensor
P0171
50
2
Bank 1
P0174
51
2
Bank 2
Continuity should exist.
DTC
Terminals
Bank
ECM or sensor
Ground
P0171
50 or 2
Ground
Bank 1
P0174
51 or 2
Ground
Bank 2
Continuity should not exist.
At idling:
When fuel pressure regulator valve
vacuum hose is connected.
235 kPa (2.4 kg/cm
2
, 34 psi)
When fuel pressure regulator valve
vacuum hose is disconnected.
294 kPa (3.0 kg/cm
2
, 43 psi)
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-1433
[VG33ER]
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7.
CHECK MASS AIR FLOW SENSOR
With CONSULT-II
1.
Install all parts removed.
2.
Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-II.
With GST
1.
Install all parts removed.
2.
Check mass air flow sensor signal in MODE 1 with GST.
OK or NG
OK
>> GO TO 8.
NG
>> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or
8.
CHECK FUNCTION OF INJECTORS
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.
Without CONSULT-II
1.
Start engine.
2.
Listen to each injector operating sound.
OK or NG
OK
>> GO TO 9.
NG
>> Perform trouble diagnosis for
.
3.3 - 4.8 g·m/sec
: at idling
12.0 - 14.9 g·m/sec
: at 2,500 rpm
3.3 - 4.8 g·m/sec
: at idling
12.0 - 14.9 g·m/sec
: at 2,500 rpm
SEF070Y
Clicking noise should be heard.
MEC703B
EC-1434
[VG33ER]
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
9.
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 injector harness connectors on left bank (for DTC P0171), right bank (for DTC P0174).
4.
Remove injector gallery assembly. Refer to
EM-80, "OUTER COMPONENT PARTS"
.
Keep fuel hose and all injectors connected to injector gallery.
The injector harness connectors on right bank (for DTC P0171), left bank (for DTC P0174) should remain
connected.
5.
Disconnect all ignition coil harness connectors.
6.
Prepare pans or saucers under each injector.
7.
Crank engine for about 3 seconds. Make sure that fuel sprays
out from injectors.
OK or NG
OK
>> GO TO 10.
NG
>> Replace injectors from which fuel does not spray out.
Always replace O-ring with new ones.
10.
CHECK INTERMITTENT INCIDENT
EC-1297, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"
.
>> INSPECTION END.
Fuel should be sprayed evenly for each injector.
SEF595Q
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