Nissan Altima L32. Manual - part 513
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
EC-1173
< COMPONENT DIAGNOSIS >
[VQ35DE]
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22.
CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and check that each
indication is within the SP value.
Is the measurement value within the SP value?
YES
>> Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to
. Then GO TO 29.
NO
>> GO TO 23.
23.
CHECK “MAS A/F SE-B1”
Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and check that the indication is within the SP
value.
Is the measurement value within the SP value?
YES
>> GO TO 24.
NO
>> More than the SP value: Replace mass air flow sensor, and then GO TO 29.
24.
REPLACE ECM
1. Replace ECM.
2. Refer to
EC-1051, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT : Special Repair
.
>> GO TO 29.
25.
CHECK INTAKE SYSTEM
Check for the cause of uneven air flow via the mass air flow sensor. Refer to the following.
• Crushed air ducts
• Malfunctioning seal in air cleaner element
• Uneven dirt in air cleaner element
• Improper specification in intake air system
Is the inspection result normal?
YES
>> GO TO 27.
NO
>> Repair or replace malfunctioning part, and then GO TO 26.
26.
CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and check that the indication is within the SP
value.
Is the measurement value within the SP value?
YES
>> INSPECTION END
NO
>> Less than the SP value: GO TO 27.
27.
CHECK “MAS A/F SE-B1”
Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and check that the indication is within the SP
value.
Is the measurement value within the SP value?
YES
>> GO TO 28.
NO
>> Less than the SP value: Replace mass air flow sensor, and then GO TO 30.
28.
CHECK INTAKE SYSTEM
Check for the cause of air leakage after the mass air flow sensor. Refer to the following.
• Disconnection, looseness, and cracks in air duct
• Looseness of oil filler cap
• Disconnection of oil level gauge
• Open stuck, breakage, hose disconnection, or cracks in PCV valve
• Disconnection or cracks in EVAP purge hose, stuck open EVAP canister purge volume control solenoid
valve
• Malfunctioning seal in rocker cover gasket
• Disconnection, looseness, or cracks in hoses, such as a vacuum hose, connecting to intake air system parts