Page 897 of 3051
6 CHECK AIR CONTROL VALVE (POWER STEERING) OPERATION-II
Check the vacuum hose for vacuum existence when steering wheel is turned.
SEF162Z
Vacuum should exist.
OK or NG
OK©GO TO 9.
NG©GO TO 7.
7 CHECK VACUUM PORT
1. Stop engine.
2. Disconnect the vacuum hose connected to the air control valve (Power steering) at the vacuum port.
3. Blow air into vacuum port.
4. Check that air flows freely.
SEF924Y
OK or NG
OK©GO TO 8.
NG©Repair or clean vacuum port.
IDLE AIR CONTROL VALVE (IACV) Ð
AUXILIARY AIR CONTROL (AAC) VALVE
QG18DE
Diagnostic Procedure (Cont'd)
EC-472
Page 898 of 3051

8 CHECK VACUUM HOSES AND TUBES
1. Disconnect vacuum hoses between the air control valve (Power steering) and vacuum port, air control valve (Power
steering) and air duct.
2. Check hoses and tubes for cracks, clogging, improper connection or disconnection.
SEF109L
OK or NG
OK©GO TO 9.
NG©Repair hoses or tubes.
9 CHECK IACV-AAC VALVE
Refer to ªComponent Inspectionº, EC-474.
OK or NG
OK©GO TO 11.
NG©GO TO 10.
10 REPLACE IACV-AAC VALVE
1. Replace IACV-AAC valve assembly.
2. Perform ªIdle Air Volume Learningº, EC-57.
Is the result CMPLT or INCMP?
CMPLT or INCMP
CMPLT©INSPECTION END
INCMP©Follow the construction of ªIdle Air Volume Learningº.
11 CHECK TARGET IDLE SPEED
1. Turn ignition switch ªOFFº.
2. Reconnect all harness connectors and vacuum hoses.
3. Start engine and warm it up to normal operating temperature.
4. Also warm up transmission to normal operating temperature.
+For M/T models, drive vehicle for 10 minutes.
5. Stop vehicle with engine running.
6. Check target idle speed.
700±50 rpm
OK or NG
OK©GO TO 12.
NG©Perform ªIdle Air Volume Learningº, EC-57.
12 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-145.
©INSPECTION END
IDLE AIR CONTROL VALVE (IACV) Ð
AUXILIARY AIR CONTROL (AAC) VALVE
QG18DE
Diagnostic Procedure (Cont'd)
EC-473
Page 899 of 3051
SEF605Y
SEF089X
Component InspectionNLEC1312IACV-AAC VALVENLEC1312S011) Disconnect IACV-AAC valve harness connector.
2) Check IACV-AAC valve resistance.
Condition Resistance
Terminal 2 and terminals 1, 3
20-24W[at 20ÉC (68ÉF)]
Terminal 5 and terminals 4, 6
3) Reconnect IACV-AAC valve harness connector.
4) Remove idle air adjusting unit assembly (IACV-AAC valve is
built-in) from engine.
(The IACV-AAC valve harness connector should remain con-
nected.)
5) Turn ignition switch ªONº and ªOFFº, and ensure the IACV-
AAC valve shaft smoothly moves forward and backward,
according to the ignition switch position.
If NG, replace the IACV-AAC valve.
IDLE AIR CONTROL VALVE (IACV) Ð
AUXILIARY AIR CONTROL (AAC) VALVE
QG18DE
Component Inspection
EC-474
Page 900 of 3051

SEF095X
Component DescriptionNLEC1313The valve timing control system is utilized to control intake valve
opening and closing timing. Engine coolant temperature signals,
engine speed and throttle position are used to determine intake
valve timing.
The intake camshaft sprocket position is regulated by oil pressure
controlled by the intake valve timing control.
When ECM sends ON signal to intake valve timing control solenoid
valve, oil pressure is transmitted to camshaft sprocket. Then, intake
side camshaft is advanced.
OperationNLEC1314
Engine operating condition
Intake valve tim-
ing control sole-
noid valveIntake valve
opening and
closing timeValve overlap
Engine coolant
temperatureEngine speed B/FUEL SCHDL Neutral switch
20ÉC (68ÉF) -
70ÉC (158ÉF)
1,150 - 4,600
rpmAbove 3 msec
OFF ON Advance Increased
Above 70ÉC
(158ÉF)Above 7 msec
Conditions other than those above OFF Normal Normal
CONSULT-II Reference Value in Data Monitor
Mode
NLEC1315
MONITOR ITEM CONDITION SPECIFICATION
INT/V SOL-B1+Engine: After warming up
+Lift up vehicle and suitable gear
positionIdle OFF
Revving engine from 2,000 to
3,000 rpmON
ECM Terminals and Reference ValueNLEC1316Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
1 Y/RIntake valve timing control
solenoid valve[Engine is running]
+Idle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Warm-up condition
+Lift up vehicle and suitable gear position
+Rev engine up from 2,000 to 3,000 rpmApproximately 0V
INTAKE VALVE TIMING CONTROL SOLENOID VALVEQG18DE
Component Description
EC-475
Page 901 of 3051
Wiring DiagramNLEC1319MODELS WITH ECM IN ENGINE COMPARTMENTNLEC1319S01
YEC754
INTAKE VALVE TIMING CONTROL SOLENOID VALVEQG18DE
Wiring Diagram
EC-476
Page 902 of 3051
MODELS WITH ECM IN CABINNLEC1319S02
YEC900
INTAKE VALVE TIMING CONTROL SOLENOID VALVEQG18DE
Wiring Diagram (Cont'd)
EC-477
Page 903 of 3051
Diagnostic ProcedureNLEC1320
1 INSPECTION START
Do you have CONSULT-II?
YesorNo
Ye s©GO TO 2.
No©GO TO 3.
2 CHECK OVERALL FUNCTION
With CONSULT-II
1. Start engine and warm it up to normal operation temperature.
2. Select ªINT/V SOL-B1º in ªDATA MONITORº mode with CONSULT-II.
3. Lift up vehicle and simulate driving in a suitable gear position.
4. Check the ªINT/V SOL-B1º singal under the following conditions.
SEF758Z
OK or NG
OK©INSPECTION END
NG©GO TO 4.
3 CHECK OVERALL FUNCTION
Without CONSULT-II
1. Start engine engine and warm it up to normal operation temperature.
2. Lift up vehicle and simulate driving in a suitable gear position.
3. Check the voltage between ECM terminal 1 and ground under the following conditions.
SEF757Z
OK or NG
OK©INSPECTION END
NG©GO TO 4.
INTAKE VALVE TIMING CONTROL SOLENOID VALVEQG18DE
Diagnostic Procedure
EC-478
Page 904 of 3051

4 CHECK POWER SUPPLY
1. Turn ignition switch ªOFFº.
2. Disconnect intake valve timing control solenoid valve harness connector.
SEF149X
3. Turn ignition switch ªONº.
4. Check voltage between terminal 1 and engine ground with CONSULT-II or tester.
SEF619X
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors F35, E75 (where fitted)
+Harness connectors M72, F44 (where fitted)
+10A fuse
+Harness for open or short between valve timing control solenoid valve and fuse
©Repair harness or connectors.
6 CHECK OUTPUT SIGNAL CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 1 and intake valve timing control solenoid valve harness connector
terminal 2. Refer to wiring diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 7.
NG©Repair open circuit or short to ground to short to power or connectors.
INTAKE VALVE TIMING CONTROL SOLENOID VALVEQG18DE
Diagnostic Procedure (Cont'd)
EC-479