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Detonation / Spark Knock

DETONATION / SPARK KNOCK - DIAGNOSIS PROCEDURE

Step Action Value(s) Yes No
1 Were the Important Preliminary Checks performed? - Go to Step 2. Go to Symptom Diagnosis .
2
  1. Fill the fuel tank with a known good grade of gasoline that has the octane rating of the value specified.
  2. Reevaluate the vehicle's performance.

Does the detonation problem still exist?		 87 - 89 octane Go to Step 3. System OK
3
  1. Inspect for low engine coolant level.
  2. Check for restricted airflow to the radiator or restricted coolant flow.
  3. Check for a faulty thermostat.
  4. Check for an incorrect coolant solution.

Is the problem found?		 - Go to Step 4. Go to Step 5.
4 Repair or replace any cooling system components as needed.
Is the repair complete?		 - System OK -
5
  1. Check the engine coolant temperature using the scan tool.
  2. Replace the Engine Coolant Temperature (ECT) sensor if the resistance is not within specifications as listed in the Diagnostic Aids for diagnostic trouble code P0118.

Is the problem found?		 - Go to Step 6. Go to Step 7.
6 Replace the ECT sensor or repair the circuit as needed.
Is the repair complete?		 - System OK -
7
  1. Check the ignition system output with a spark tester.
  2. Inspect the spark plugs for the proper heat range and gap.
  3. Check for the proper operation of the ignition controls.

Is the ignition system operating properly?		 - Go to Step 9. Go to Step 8.
8 Repair or replace the ignition system components as needed.
Is the repair complete?		 - System OK -
9
  1. Connect the scan tool to the Data Link Connector (DLC).
  2. Road test the vehicle at the speed of the complaint.
  3. Monitor the long term fuel trim reading from the scanner data stream.

Is the long term fuel trim reading above the value specified?		 20% Go to "DIAGNOSTIC AIDS " for DTC P0171: Fuel Trim System Lean Bank 1 . Go to Step 10.
10 Check the fuel system pressure.
Is the problem found?		 310 kPa (45 psi) Go to Step 11. Go to Step 12.
11 Repair or replace the fuel system components as needed.
Is the repair complete?		 - System OK -
12
  1. Inspect for carbon buildup inside the engine.
  2. Remove the carbon with a top engine cleaner. Follow the instructions supplied with the product.
  3. Check the basic engine parts such as the camshaft, the cylinder head, the pistons, etc. for excessive wear.
  4. Replace any excessively worn parts.

Is the procedure complete?		 - Go to Step 13. -
13
  1. Check the exhaust gas recirculation valve for proper operation.
  2. Check the air intake system for proper operation.
  3. Check the torque converter clutch operation and transaxle shift points.
  4. Check the service bulletins for Programmable Read-Only Memory (PROM) updates.
  5. Check the cylinder compression.
  6. Repair or replace any faulty components.

Are all checks and repairs complete?		 - System OK -
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