Page 719 of 2267

Diagnostic ProcedureNCEC0285
1 CHECK POWER SUPPLY
1. Turn ignition switch ªOFFº.
2. Disconnect IACV-AAC valve harness connector.
NEF246A3. Turn ignition switch ªONº.
4. Check voltage between terminal 2, 5 and ground with CONSULT-II or tester.
SEF352QAVoltage: Battery voltage
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E90, F73
I10A fuse
IHarness for open or short between IACV-AAC valve and battery
©Repair harness or connectors.
3 CHECK OUTPUT SIGNAL CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between
ECM terminal 6 and IACV-AAC valve terminal 1,
ECM terminal 7 and IACV-AAC valve terminal 4,
ECM terminal 15 and IACV-AAC valve terminal 3,
ECM terminal 16 and IACV-AAC valve terminal 6.
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 4.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
Throttle body
Throttle position sensor
harness connector
IACV-AAC valve
harness connector
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð
AUXILIARY AIR CONTROL (AAC) VALVEQG16I18DE
Diagnostic Procedure
EC-277
Page 720 of 2267
4 CHECK AIR CONTROL VALVE (POWER STEERING) OPERATION-I
1. Reconnect the ECM harness connector and IACV-AAC valve harness connector.
2. Disconnect the vacuum hose connected to the air control valve (Power steering) at the intake air duct.
3. Start engine and let it idle.
4. Check vacuum hose for vacuum existence.
SEF162Z
Vacuum does not exist or slightly exist.
OK or NG
OK©GO TO 5.
NG©Replace air control valve (Power steering).
5 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 8.
NG©GO TO 6.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð
AUXILIARY AIR CONTROL (AAC) VALVEQG16I18DE
Diagnostic Procedure (Cont'd)
EC-278
Page 721 of 2267
6 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 7.
NG©Repair or clean vacuum port.
7 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 8.
NG©Repair hoses or tubes.
8 CHECK IACV-AAC VALVE
Refer to ªComponent Inspectionº, EC-QG-281.
OK or NG
OK©GO TO 10.
NG©GO TO 9.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð
AUXILIARY AIR CONTROL (AAC) VALVEQG16I18DE
Diagnostic Procedure (Cont'd)
EC-279
Page 722 of 2267
9 REPLACE IACV-AAC VALVE
1. Replace IACV-AAC valve assembly.
2. Perform ªIdle Air Volume Learningº, EC-QG-33.
Is the result CMPLT or INCMP?
CMPLT or INCMP
CMPLT©INSPECTION END
INCMP©Follow the instruction of ªIdle Air Volume Learningº.
10 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.
IDrive vehicle for 10 minutes.
5. Stop vehicle with engine running.
6. Check target idle speed.
700 50 rpm
OK or NG
OK©GO TO 11.
NG©Perform ªIdle Air Volume Learningº, EC-QG-33.
11 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-QG-102.
©INSPECTION END
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð
AUXILIARY AIR CONTROL (AAC) VALVEQG16I18DE
Diagnostic Procedure (Cont'd)
EC-280
Page 723 of 2267
Component InspectionNCEC0286IACV-AAC VALVENCEC0286S011) 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.
SEF353QA
SEF089X
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð
AUXILIARY AIR CONTROL (AAC) VALVEQG16I18DE
Component Inspection
EC-281
Page 724 of 2267

Component DescriptionNCEC0295The ECM consists of a microcomputer, diagnostic test mode
selector, and connectors for signal input and output and for power
supply. The ECM controls the engine.
On Board Diagnosis LogicNCEC0296
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0605
0605IECM calculation function is malfunctioning.IECM
DTC Confirmation ProcedureNCEC0297NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 9 seconds
before conducting the next test.
With CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine.
4) Run engine for at least 1 second at idle speed.
5) If 1st trip DTC is detected, go to ªDiagnostic Procedureº, EC-
QG-282.
With GST
Follow the procedure ªWith CONSULT-IIº above.
Diagnostic Procedure=NCEC0298
1 INSPECTION START
With CONSULT-II
1. Turn ignition switch ªONº.
2. Select ªSELF DIAG RESULTSº mode with CONSULT-II.
3. Touch ªERASEº.
4. Perform ªDTC Confirmation Procedureº.
See previous page.
5. Is the 1st trip DTC P0605 displayed again?
With GST
1. Turn ignition switch ªONº.
2. Select MODE 4 with GST.
3. Touch ªERASEº.
4. Perform ªDTC Confirmation Procedureº.
See previous page.
5. Is the 1st trip DTC P0605 displayed again?
YesorNo
Ye s©GO TO 2.
No©INSPECTION END
SEF093X
NEF068A
DTC P0605 ECMQG16I18DE
Component Description
EC-282
Page 726 of 2267

Component DescriptionNCEC0513The 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.
OperationNCEC0514
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
NCEC0515
MONITOR ITEM CONDITION SPECIFICATION
INT/V SOL-B1IEngine: After warming upIdle OFF
Revving engine with full throttle
opening (Under 4,600 rpm)ON
ECM Terminals and Reference ValueNCEC0516Specification data are reference values and are measured between each terminal and engine 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.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
1 Y/RIntake valve timing control
solenoid valveIgnition ªONºBATTERY VOLTAGE
(11 - 14V)
On Board Diagnosis LogicNCEC0517
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P 1111
1111IAn improper voltage signal is entered to ECM through
intake valve timing control solenoid valve.IHarness or connectors
(The intake valve timing control solenoid valve
circuit is open or shorted.)
IIntake valve timing control solenoid valve
SEF095X
D T C P 1111 I N TA K E VA LV ETIMING CONTROL
SOLENOID VALVEQG16I18DE
Component Description
EC-284
Page 727 of 2267
DTC Confirmation ProcedureNCEC0518NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 9 seconds
before conducting the next test.
With CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 5 seconds.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº, EC-
QG-287.
Without CONSULT-II
Follow the procedure ªWith CONSULT-IIº above.
NEF121A
D T C P 1111 I N TA K E VA LV ETIMING CONTROL
SOLENOID VALVEQG16I18DE
DTC Confirmation Procedure
EC-285