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Inspection procedure 16: Knocking
 
 
 
 
COMMENT
  • Incases such as the above, the cause is probably that the detonation control is defective or the heat value of the spark plug is inappropriate.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this case: )
  • Defective knock sensor.
  • Incorrect heat value of the spark plug.
  • Poor compression.
  • Malfunction of the ECM.

 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
Using scan tool (M.U.T.-III), read the diagnostic trouble code (DTC).
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
(1) Connect scan tool (M.U.T-III). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) .
(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 stored?
Refer to Diagnostic Trouble Code Chart .
Go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-III), 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 .
  1. Item 32: Knock Retard
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
Go to Step 3.
Refer to DTC P0327 - Knock Sensor Circuit Low , DTC P0328 - Knock Sensor Circuit High .
 
STEP 3. 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.
Go to Step 4.
 
STEP 4. Check the compression pressure.
Refer to GROUP 11A, On-vehicle Service - Compression Pressure Check .
Is the compression pressure normal?
  • Check the following items, and repair or replace the defective items.
    1. Check if fuel is contaminated.
    2. Check if the foreign materials (water, diesel fuel, etc.) got into fuel.
  • Then confirm that the malfunction symptom is eliminated.
Repair it. Then confirm that the malfunction symptom is eliminated.