Idle/Throttle Speed Control Unit: Testing and Inspection

1. Start the engine and run it at idle.
2. Disconnect the IAC valve connector and verify that the engine idles rough or stalls.
3. If the idle does not change, do as follows.

New Generation Star (NGS) Tester, Connected to DLC-2:

A) Connect the Special Service Tool (SST) New Generation Star (NGS) tester.
B) Verify that diagnostic trouble code No. P0505 is not displayed. If code No. P0505 is shown, carry out troubleshooting of the code No. P0505.
C) Change the duty value of the Idle Air Control (IAC) valve to 100% by using the SIMULATION TEST function and verify that the idle speed increases.
1. If the idle speed increases, replace the Powertrain Control Module (PCM).
2. If the idle speed does not change, replace the BAC valve.

4. Warm up the engine to normal operating temperature and run it at idle.
5. Turn the electrical loads on and verify that the engine speed is within the specification.

Idle Speed Specifications:

6. If not as specified, check the related switches and wiring harnesses.


SYSTEM INSPECTION
1 Verify that the engine coolant temperature is below 20°C (68°F).

DLC-1 Idle Check Jumper Location:

2. Connect the data link connector terminals TEN and GND with a jumper wire.
3. Start the engine.
4. Verify that the idle speed decreases gradually as the engine warms up.


Air Valve
1. Remove the BAC valve.

Air Valve Inspection:

2. Circulate water in the BAC valve coolant passage to cool the air valve.
3. Circulate hot water in the BAC valve coolant passage and verify that the air valve operates.
4. If not, replace the BAC valve.

Idle Air Control Valve
1. Remove the throttle body.

Idle Air Control Valve Resistance Testing:

2. Measure the resistance of the idle air control valve.

Resistance: 10.7-12.3 Ohms at 20°C (68°F)

3. If not as specified, replace the BAC valve.