Inspection Procedure 14: Knocking

COMMENTS ON TROUBLE SYMPTOM

Failure is possibly caused by failed detonation control system and improper thermal value of the spark plug

PROBABLE CAUSES

Failed detonation sensor
Failed detonation control system
Failed spark plug
Failed ignition system
Failed engine-ECU <M/T> or engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is diagnosis code set?

	Inspection chart for diagnosis code (Refer to ).

	Go to Step 2 .

STEP 2. Visual check of ignition spark.

Remove the spark plug and install it to the ignition coil.
Connect the ignition coil connector.
Remove all injector connectors.
At the engine start, check each spark plug produces a spark.

Q. Is the check result normal?

	Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.

	Go to Step 3 .

STEP 3. Check spark plug

Check spark plug itself (Refer to GROUP 16 - Ignition System - On-vehicle Service - Spark Plug Check and Cleaning <6G72 without catalytic converter> or Spark Plug Check and Cleaning <6G72 with catalytic converter> ).

Q. Is the check result normal?

	Check ignition circuit system (Refer to Inspection Procedure 26 ).

	Replace the spark plug.