Inspection Procedure 14
INSPECTION PROCEDURE 14: The Engine Stalls When DeceleratingCOMMENT
- The intake air volume may be insufficient due to a defective idle air control motor system.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of the IAC system.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Check if the battery terminal is disconnected.
Q: Has the battery terminal been disconnected lately?
YES: Start the engine and let it run at idle for approximate 10 minutes after engine warm up. Then if a malfunction occurs, go to step 2.
NO: Go to Step 2.
STEP 2. Using scan tool MB991958, read the diagnostic trouble code (DTC).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 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. Diagnostic Trouble Code Descriptions
NO: Go to Step 3.
STEP 3. Using scan tool MB991958, check data list.
1. Turn the ignition switch to the "ON" position.
2. Check the following item in the data list. Refer to, Data List Reference Table. Data List Reference Table & Normal Scan Data Values
a. Item 14: Throttle Position Sensor.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 4.
NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 4. Using scan tool MB991958, check actuator test.
1. Turn the ignition switch to the "ON" position.
2. Check the following item in the actuator test. Refer to, Actuator Test Reference Table. Actuator Test Reference Table
a. Item 10: EGR Vacuum Regulator Solenoid Valve.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?
YES: Go to Step 5.
NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 5. Using scan tool MB991958, check data list item 45: Idle Air Control Position.
1. Start the engine and run at idle.
2. Set scan tool MB991958 to the data reading mode for item 45, Idle Air Control Position.
a. The idle air control motor should drop to the 0 - 2 position during deceleration (from 1,000 r/min or more).
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operation properly?
YES: Check the following items, and repair, replace or clean the defective sections.
a. Check the ignition coil, spark plugs, spark plug cables.
b. Check the throttle valve area. (Refer to, On-vehicle Service - Throttle Body Cleaning.)
Then confirm that the malfunction symptom is eliminated.
NO: Refer to, DTC P0500 - Vehicle Speed Sensor. P0500