P0505

SYSTEM DESCRIPTION
This system automatically controls engine idle speed to a specified level. Idle speed is controlled through fine adjustment of the amount of air which bypasses the throttle valve via IACV-AAC valve. The IACV-AAC valve repeats ON/OFF operation according to the signal sent from the ECM The camshaft position sensor detects the actual engine speed and sends a signal to the ECM. The ECM then controls the ON/OFF time of the IACV-AAC valve so that engine speed coincides with the target value memorized in ECM. The target engine speed is the lowest speed at which the engine can operate steadily. The optimum value stored in the ECM is determined by taking into consideration various engine conditions, such as during warm up, deceleration, and engine load (air conditioner and power steering.)




COMPONENT DESCRIPTION
IACV-AAC Valve
The IACV-AAC valve is moved by ON/OFF pulses from the ECM. The longer the ON pulse, the greater the amount of air that will flow through the valve. The more air that flows through the valve, the higher the idle speed.




CONSULT Reference Value in Data Monitor Mode
Specification data are reference values.




ECM Terminals and Reference Value
Specification data are reference values and are measured between each terminal and 32 (ECM ground)




On Board Diagnosis Logic

DTC Confirmation Procedure

NOTE:
- If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.
- Perform "PROCEDURE FOR MALFUNCTION A" first. If 1st trip DTC cannot be confirmed, perform "PROCEDURE FOR MALFUNCTION B".

PROCEDURE FOR MALFUNCTION A

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10.5V with ignition switch "ON".

With CONSULT
1. Turn ignition switch "ON".




2. Select "DATA MONITOR" mode with CONSULT.
3. Wait at least 2 seconds.
4. If 1St trip DTC is detected, go to "Diagnostic Procedure" below.

With GST
1. Turn ignition switch "ON" and wait at least 2 seconds.
2. Select "MODE 7" with GST.
3. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

Without Scan Tool
1. Turn ignition switch "ON" and wait at least 2 seconds.
2. Turn ignition switch "OFF", wait at least 5 seconds and then turn "ON".
3. Perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.




4. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

PROCEDURE FOR MALFUNCTION B TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V at idle.

With CONSULT
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Turn ignition switch "ON" again and select "DATA MONITOR" mode with CONSULT.
4. Start engine and run it for at least 1 minute at idle speed.
5. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

With GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Start engine again and run it for at least 1 minute at idle speed.
4. Select "MODE 7" with GST.
5. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

Without Scan Tool
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Start engine again and run it for at least 1 minute at idle speed.
4. Turn ignition switch "OFF", wait at least 5 seconds and then turn "ON".
5. Perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.
6. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

EC-AAC/V-01:

EC-AAC/V-01 Connectors View:

Wiring Diagram

Diagnostic Procedure

Step 1:

Step 2:

Step 3:

Step 4:

Step 5:

Step 6:

Component Inspection




IACV-AAC VALVE
1. Disconnect IACV-AAC valve harness connector.
2. Remove IACV-AAC valve.
- Check IACV-AAC valve resistance.
Resistance:
Approximately 10 ohms [at 20° (68°F)]
- Check plunger for seizing or sticking.
- Check for broken spring.

3. Supply battery voltage between IACV-AAC valve connector terminals.
Plunger should move.