Inspection Procedure 17

COMMENT
- There may be a sudden change in air flow through the IAC, causing the vehicle to decelerate rapidly for an instant.

TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of the IAC system.

DIAGNOSIS

Required Special Tool:
MB991502: Scan Tool (MUT-II)




STEP 1.Using scan tool MB991502, read the diagnostic trouble code (DTC).

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Read the DTC.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC is output?

YES: Refer to Diagnostic Trouble Code Chart.

NO: Go To Step 2.




STEP 2.Check the idle air control (IAC) motor operation sound.
1. Check that the engine coolant temperature is 20 °C (68 °F) or below.

NOTE: If necessary, you can disconnect the engine coolant temperature sensor connector and connect the harness side of the connector to another engine coolant temperature sensor that is at 20 °C (68 °F) or below.

2. Check the operation sound of the IAC motor can be heard after the ignition is switched to the "ON" position (but without starting the engine).
- An operation sound should heard.
3. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Did you hear the operation sound?

YES: Go to Step 3.

NO: Refer to DTC P0506 - Idle Control System RPM Lower Than Expected <3.0L Engine> or DTC P0506 - Idle Control System RPM Lower Than Expected <3.5L Engine>, DTC P0507- Idle Control System RPM Higher Than Expected <3.0L Engine> or DTC P0507 - Idle Control System RPM Higher Than Expected <3.5L Engine>.




STEP 3.Using scan tool MB991502, check data list.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Check the following items in the data list. Refer to Data List Reference Table.
a. Item 14: Throttle Position Sensor.
b. Item 26: Closed Throttle Position Switch <3.0L Engine>

4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES: Carry out the following cleaning or adjustment.
a. Clean the throttle valve area.
b. Check and adjust the fixed SAS <3.0L Engine>

NO: Repair or replace. Then confirm that the malfunction symptom is eliminated.