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Inspection procedure 13: The engine stalls when decelerating
 
 
 
 
COMMENT
  • Abnormal air/fuel ratio or other similar defects due to insufficient intake air volume and defective EGR system is suspected to be the causes.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this case:)
  • Ignition system failed.
  • Dirtiness around throttle valve.
  • EGR system failed.
  • ECM failed.

 
 
DIAGNOSIS
Required Special Tool:
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: V.C.I.
    • MB991827: USB Cable
    • MB991910: Main Harness A
STEP 1. Check if the EGR valve sounds during initialization.
Is the initialization sound heard in the EGR valve?
Go to Step 2.
Refer to GROUP 17, Emission Control - Exhaust Gas Recirculation (EGR) System - EGR Valve (stepper motor) Check .
 
STEP 2. Using scan tool MB991958, read the diagnostic trouble code (DTC).
cautionTo 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.
Is any DTC set?
Refer to, Diagnostic Trouble Code Chart .
Go to Step 3.
 
STEP 3. Inspection of throttle body (throttle valve area) for dirtiness.
Is the throttle valve area dirty?
Refer to, Throttle Body (throttle valve area) Cleaning .
Go to Step 4.
 
STEP 4. Using scan tool MB991958, check data list.
(1) Turn the ignition switch to the "ON" position.
(2) Check the following items in the data list. Refer to Data List Reference Table .
  1. Item 11: Accelerator Pedal Position Sensor (main)
  2. Item 12: Accelerator Pedal Position Sensor (sub)
  3. Item 13: Throttle Position Sensor (main)
  4. Item 15: Throttle Position Sensor (sub)
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Are they operating properly?
Go to Step 5.
Repair or replace it. Then confirm that the malfunction symptom is eliminated.
 
STEP 5. Check the spark plugs.
Refer to GROUP 16, Ignition System - On-vehicle Service - Spark Plug Check and Cleaning .
Are there any abnormalities?
Replace the spark plug. Then confirm that the malfunction symptom is eliminated.
Check the ignition coil (Refer to GROUP 16, Ignition System - On-vehicle Service - Ignition Coil Check ). Then confirm that the malfunction symptom is eliminated.