Nissan Frontier. Manual — part 509
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
EC-607
< DTC/CIRCUIT DIAGNOSIS >
[VQ40DE FOR USA AND CANADA]
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DTC/CIRCUIT DIAGNOSIS
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
Description
INFOID:0000000009481238
The specification (SP) value indicates the tolerance of the value that is displayed in “SPEC” of “DATA MONI-
TOR” mode of CONSULT during normal operation of the Engine Control System. When the value in “SPEC” of
“DATA MONITOR” mode is within the SP value, the Engine Control System is confirmed OK. When the value
“SPEC” of “DATA MONITOR” mode is NOT within the SP value, the Engine Control System may have one or
more malfunctions.
The SP value is used to detect malfunctions that may affect the Engine Control System, but will not illuminate
the MIL.
The SP value will be displayed for the following three items:
• B/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board correc-
tion)
• A/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)
• MAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Testing Condition
INFOID:0000000009481239
• Vehicle driven distance: More than 5,000 km (3,107 miles)
• Barometric pressure: 98.3 - 104.3 kPa (1.003 - 1.064 kg/cm
2
, 14.25 - 15.12 psi)
• Atmospheric temperature: 20 - 30
°C (68 - 86°F)
• Engine coolant temperature: 75 - 95
°C (167 - 203°F)
• Transmission: Warmed-up*
1
• Electrical load: Not applied*
2
• Engine speed: Idle
*1: After the engine is warmed up to normal operating temperature, drive vehicle until “FLUID TEMP SE” (A/T
fluid temperature sensor signal) indicates more than 60
°C (140°F).
*2: Rear window defogger switch air conditioner switch, lighting switch are OFF. Steering wheel is straight
ahead.
Inspection Procedure
INFOID:0000000009481240
NOTE:
Perform “SPEC” of “DATA MONITOR” mode in maximum scale display.
1. Perform
2. Confirm that the testing conditions indicated above are met.
3. Select “B/FUEL SCHDL”, “A/F ALPHA-B1”, “A/F ALPHA-B2” and “MAS A/F SE-B1” in “SPEC” of “DATA
MONITOR” mode with CONSULT.
4. Make sure that monitor items are within the SP value.
5. If NG, go to
Diagnosis Procedure
INFOID:0000000009481241
OVERALL SEQUENCE
EC-608
< DTC/CIRCUIT DIAGNOSIS >
[VQ40DE FOR USA AND CANADA]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
JMBIA1468GB
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
EC-609
< DTC/CIRCUIT DIAGNOSIS >
[VQ40DE FOR USA AND CANADA]
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DETAILED PROCEDURE
1.
CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Confirm that the testing conditions are met. Refer to
.
3. Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that
each indication is within the SP value.
NOTE:
PBIB3214E
EC-610
< DTC/CIRCUIT DIAGNOSIS >
[VQ40DE FOR USA AND CANADA]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
Check “A/F ALPHA-B1”, “A/F ALPHA-B2” for approximately 1 minute because they may fluctuate. It is NG
if the indication is out of the SP value even a little.
OK or NG
OK
>> GO TO 17.
NG (Less than the SP value)>>GO TO 2.
NG (More than the SP value)>>GO TO 3.
2.
CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK
>> GO TO 4.
NG (More than the SP value)>>GO TO 19.
3.
CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK
>> GO TO 6.
NG (More than the SP value)>>GO TO 6.
NG (Less than the SP value)>>GO TO 25.
4.
CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Stop the engine.
2. Disconnect PCV hose, and then plug it.
3. Start engine.
4. Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that
each indication is within the SP value.
OK or NG
OK
>> GO TO 5.
NG
>> GO TO 6.
5.
CHANGE ENGINE OIL
1. Stop the engine.
2. Change engine oil.
NOTE:
This symptom may occur when a large amount of gasoline is mixed with engine oil because of driving
conditions (such as when engine oil temperature does not rise enough since a journey distance is too
short during winter). The symptom will not be detected after changing engine oil or changing driving con-
ditions.
>> INSPECTION END
6.
CHECK FUEL PRESSURE
Check fuel pressure. (Refer to
OK or NG
OK
>> GO TO 9.
NG (Fuel pressure is too high)>>Replace fuel pressure regulator, refer to
.
GO TO 8.
NG (Fuel pressure is too low)>>GO TO 7.
7.
DETECT MALFUNCTIONING PART
1. Check the following.
-
Clogged and bent fuel hose and fuel tube
-
Clogged fuel filter
-
Fuel pump and its circuit (Refer to
.)
2. If NG, repair or replace the malfunctioning part. (Refer to Diagnosis Procedure.)
If OK, replace fuel pressure regulator.
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