Page 769 of 3051

CONSULT-II Reference Value in Data Monitor
Mode
NLEC0280
MONITOR ITEM CONDITION SPECIFICATION
IACV-AAC/V+Engine: After warming up
+Air conditioner switch: OFF
+Shift lever: ªNº
+No-loadIdle 5 - 25 steps
2,000 rpm Ð
ECM Terminals and Reference ValueNLEC0281Specification 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.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
6
7
15
16BR
LG
P
ORIACV-AAC valve[Engine is running]
+Warm-up condition
+Idle speed0.1 - 14V
On Board Diagnosis LogicNLEC0282
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0505
0505+An improper voltage signal is sent to ECM through the
valve.+Harness or connectors
(The IACV-AAC valve circuit is open.)
+IACV-AAC valve
SEF058Y
DTC Confirmation ProcedureNLEC0283NOTE:
+If ªDTC Confirmation Procedureº has been previously
conducted, always turn ignition switch ªOFFº and wait at least
9 seconds before conducting the next test.
+If the target idle speed is out of the specified value, per-
form ªIdle Air Volume Learningº, EC-57, before conducting
ªDTC Confirmation Procedureº. For the target idle speed,
refer to ªService Data and Specifications (SDS)º, EC-547.
With CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and warm it up to normal operating temperature.
4) Rev engine from idle to 2,000 rpm 20 times.
If 1st trip DTC is detected, go to ªDIAGNOSTIC
PROCEDUREº, EC-324.
With GST
Follow the procedure ªWith CONSULT-IIº above.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
QG18DE
CONSULT-II Reference Value in Data Monitor Mode
EC-344
Page 770 of 3051
Wiring DiagramNLEC0284MODELS WITH ECM IN ENGINE COMPARTMENTNLEC0284S01
YEC668
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
QG18DE
Wiring Diagram
EC-345
Page 771 of 3051
MODELS WITH ECM IN CABINNLEC0284S02
YEC888
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
QG18DE
Wiring Diagram (Cont'd)
EC-346
Page 772 of 3051
Diagnostic ProcedureNLEC0285
1 CHECK POWER SUPPLY
1. Turn ignition switch ªOFFº.
2. Disconnect IACV-AAC valve harness connector.
NEF316A
3. Turn ignition switch ªONº.
4. Check voltage between terminal 2, 5 and ground with CONSULT-II or tester.
SEF343X
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
+15A fuse
+Harness connectors E76, F36 (where fitted)
+Harness connectors M72, F44 (where fitted)
+Harness connectors M11, E106 (LHD models) (where fitted)
+Harness connectors M78, E120 (RHD models) (where fitted)
+Harness for open or short between fuse and ECM relay
+ECM relay
+Harness for open or short between IACV-AAC and ECM relay.
©Repair harness or connectors, or replace fuse or ECM relay.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
QG18DE
Diagnostic Procedure
EC-347
Page 773 of 3051

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.
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) VALVE
QG18DE
Diagnostic Procedure (Cont'd)
EC-348
Page 774 of 3051
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-351.
OK or NG
OK©GO TO 10.
NG©GO TO 9.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
QG18DE
Diagnostic Procedure (Cont'd)
EC-349
Page 775 of 3051
9 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.
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.
+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 11.
NG©Perform ªIdle Air Volume Learningº, EC-57.
11 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-145.
©INSPECTION END
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
QG18DE
Diagnostic Procedure (Cont'd)
EC-350
Page 776 of 3051
SEF605Y
SEF089X
Component InspectionNLEC0286IACV-AAC VALVENLEC0286S011) 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.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
QG18DE
Component Inspection
EC-351