Page 849 of 2898

23 CHECK IACV-AAC VALVE CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check IACV-AAC valve circuit for open and short. Refer to ªDiagnostic Procedureº, EC-380.
OK or NG
OK©GO TO 24.
NG©1. Repair or replace.
2. GO TO 25.
24 REPLACE IACV-AAC VALVE
Replace IACV-AAC valve.
©GO TO 25.
25 PERFORM IDLE AIR VOLUME LEARNING
Refer to ªIdle Air Volume Learningº, EC-57.
Which is the result CMPLT or INCMP?
CMPLT or INCMP
CMPLT©GO TO 26.
INCMP©1. Follow the construction of ªIdle Air Volume Learningº.
2. GO TO 21.
26 CHECK TARGET IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select ªENG SPEEDº in ªDATA MONITORº mode with CONSULT-II.
3. Check idle speed.
M/T: 700±50 rpm
A/T: 800±50 rpm (in ªPº or ªNº position)
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
M/T: 700±50 rpm
A/T: 800±50 rpm (in ªPº or ªNº position)
OK or NG
OK©GO TO 28.
NG©GO TO 27.
27 CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of a problem, but this is rarely
the case.)
2. Perform initialization of NATS system and registration of NATS ignition key IDs. Refer to ªNATS (Nissan Anti-Theft
System)º, EC-74.
©GO TO 21.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONQG
Basic Inspection/Sedan (Cont'd)
EC-125
Page 850 of 2898
28 CHECK IGNITION TIMING
1. Start engine and warm it up to normal operating temperature.
2. Check ignition timing at idle using a timing light.
SEF984U
Ignition timing:
M/T 8ɱ5É BTDC
A/T 10ɱ5É BTDC (in ªPº or ªNº position)
OK or NG
OK©GO TO 36.
NG©GO TO 29.
29 CHECK TIMING CHAIN INSTALLATION
Check timing chain installation. Refer to EM-28, ªInstallationº.
OK or NG
OK©GO TO 27.
NG©1. Repair the timing chain installation.
2. GO TO 21.
30 CHECK IGNITION TIMING
1. Start engine and let it idle.
2. Check ignition timing at idle using a timing light.
SEF984U
Ignition timing:
M/T 8ɱ5É BTDC
A/T 10ɱ5É BTDC (in ªPº or ªNº position)
OK or NG
OK©GO TO 36.
NG©GO TO 21.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONQG
Basic Inspection/Sedan (Cont'd)
EC-126
Page 851 of 2898

31 PERFORM IDLE AIR VOLUME LEARNING
Refer to ªIdle Air Volume Learningº, EC-57.
Which is the result CMPLT or INCMP?
CMPLT or INCMP
CMPLT©GO TO 32.
INCMP©1. Follow the construction of ªIdle Air volume Learningº.
2. GO TO 31.
32 CHECK TARGET IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select ªENG SPEEDº in ªDATA MONITORº mode with CONSULT-II.
3. Check idle speed.
M/T: 700±50 rpm
A/T: 800±50 rpm (in ªPº or ªNº position)
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
M/T: 700±50 rpm
A/T: 800±50 rpm (in ªPº or ªNº position)
OK or NG
OK©GO TO 34.
NG©GO TO 33.
33 CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function.
(ECM may be the cause of a problem, but this is rarely the case.)
2. Perform initialization of NATS system and registration of NATS ignition key IDs. Refer to ªNATS (Nissan Anti-Theft
System)º, EC-74.
©GO TO 31.
34 CHECK IGNITION TIMING AGAIN
Check ignition timing again. Refer to Test No. 30.
OK or NG
OK©GO TO 36.
NG©GO TO 35.
35 CHECK TIMING CHAIN INSTALLATION
Check timing chain installation. Refer to EM-28, ªInstallationº.
OK or NG
OK©GO TO 33.
NG©1. Repair the timing chain installation.
2. GO TO 31.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONQG
Basic Inspection/Sedan (Cont'd)
EC-127
Page 852 of 2898

36 ERASE UNNECESSARY DTC
After this inspection, unnecessary DTC No. might be displayed.
Erase the stored memory in ECM and TCM (Transmission control module).
Refer to ªHow to Erase Emission-Related Diagnostic Informationº, EC-70 and AT-52, ªHOW TO ERASE DTCº.
©INSPECTION END
Basic Inspection/HatchbackNJEC1785MODELS WITH THROTTLE POSITION SWITCHNJEC1785S01Precaution:
Perform Basic Inspection without electrical or mechanical
loads applied;
+Headlamp switch is OFF,
On vehicle equipped with daytime light systems, set lighting
switch to the 1st position to light only small lamps.
+Air conditioner switch is OFF,
+Rear window defogger switch is OFF,
+Steering wheel is in the straight-ahead position, etc.
1 INSPECTION START
1. Check service records for any recent repairs that may indicate a related problem, or a current need for scheduled
maintenance.
2. Open engine hood and check the following:
+Harness connectors for improper connections
+Vacuum hoses for splits, kinks and improper connections
+Wiring for improper connections, pinches and cuts
+Air cleaner clogging
+Hoses and ducts for leaks
SEF983U
©GO TO 2.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONQG
Basic Inspection/Sedan (Cont'd)
EC-128
Page 853 of 2898
2 CHECK THROTTLE OPENER OPERATION-I
Confirm that there is a clearance between throttle drum and stopper.
SEF850Y
OK or NG
OK©GO TO 4.
NG©GO TO 3.
3 CHECK THROTTLE OPENER FIXING BOLTS
Check throttle opener fixing bolts for loosening.
OK or NG
OK©1. Repair or replace throttle body assembly.
2. GO TO 2.
NG©1. Retighten the fixing bolts.
2. GO TO 2.
4 CHECK THROTTLE OPENER OPERATION-II
1. Start engine and let it idle.
2. Confirm that throttle opener rod moves backward and there is a clearance between throttle drum and throttle opener
rod.
SEF850Y
OK or NG
OK©GO TO 7.
NG©GO TO 5.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONQG
Basic Inspection/Hatchback (Cont'd)
EC-129
Page 854 of 2898
5 CHECK VACUUM SOURCE FOR THROTTLE OPENER
1. Disconnect vacuum hose connected to throttle opener.
2. Check vacuum existance with engine running.
SEF155Y
OK or NG
OK©1. Repair or replace throttle body assembly.
2. GO TO 2.
NG©GO TO 6.
6 CHECK VACUUM HOSE
1. Stop engine.
2. Remove the vacuum hose.
3. Check the vacuum hose for splits, kinks and clogging.
SEF109L
OK or NG
OK©1. Clean vacuum port by blowing air.
2. GO TO 4.
NG©1. Replace vacuum hose.
2. GO TO 4.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONQG
Basic Inspection/Hatchback (Cont'd)
EC-130
Page 855 of 2898
7 CHECK THROTTLE DRUM OPERATION
Confirm that throttle drum moves to contact the stopper.
SEF850Y
OK or NG
OK©GO TO 10.
NG©GO TO 8.
8 CHECK ACCELERATOR WIRE INSTALLATION
1. Stop engine.
2. Check accelerator wire for slack.
OK or NG
OK©GO TO 9.
NG©1. Adjust accelerator wire. Refer to FE-3, ªAdjusting Accelerator Wireº.
2. GO TO 7.
9 CHECK THROTTLE VALVE OPERATION
1. Remove intake air ducts.
2. Check throttle valve operation when moving throttle drum by hand.
OK or NG
OK©1. Retighten the throttle drum fixing nuts.
2. GO TO 7.
NG©1. Clean the throttle body and throttle valve.
2. GO TO 7.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONQG
Basic Inspection/Hatchback (Cont'd)
EC-131
Page 856 of 2898
10 CHECK THROTTLE POSITION SWITCH CLOSED POSITION-I (If throttle opener is equipped)
NOTE:
Always check ignition timing before performing the following.
1. Warm up engine to normal operating temperature.
2. Stop engine.
3. Remove the vacuum hose connected to the throttle opener.
4. Connect suitable vacuum hose to vacuum pump as shown below.
SEF793WA
5. Apply vacuum [more than þ40.0 kPa (±400 mbar, þ300 mmHg, þ11.81 inHg)] until the throttle drum is free from the
throttle opener rod.
Models with CONSULT-II©GO TO 11.
Models without CON-
SULT-II©GO TO 15.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONQG
Basic Inspection/Hatchback (Cont'd)
EC-132