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6E–270 ENGINE DRIVEABILITY AND EMISSIONS Detonation/Spark Knock Symptom
Step Action Value(s) Yes No 1 DEFINITION: Was the “On-Board Diagnostic (OBD) System Check” — Go to Step 2 Go to OBD System Check 2 1. Perform a bulletin search. correct the condition as instructed in the bulletin. Was a bulletin found that addresses the symptom? — Verify repair Go to Step 3 3 Was a visual/physical check performed? — Go to Step 4 Go to Visual/Physic al Check 4 If Tech 2 readings are normal (refer to Typical Scan Values) and there are no engine mechanical faults, fill Is detonation present? — Go to Step 5 Verify repair 5 1. Check the transmission range switch circuit. Use Tech 2 and be sure Tech 2 indicates that the vehicle 2. If a problem is found, diagnose and repair the transmission range switch as necessary (refer to Was a problem found? — Verify repair Go to Step 6 6 1. Check TCC operation. Refer to 4L30-E Transmission Diagnosis. 2. If a problem is found, repair as necessary. Was a problem found? — Verify repair Go to Step 7 7 1. Check for obvious overheating problems: D Low engine coolant. D Restricted air flow to radiator, or restricted D Correct coolant solution should be a 50/50 mix Engine Cooling. 2. If a problem is found, repair as necessary. Was a problem found? — Verify repair Go to Step 8 8 1. Check fuel pressure. Refer to Chart Fuel System Pressure Test. 2. If a problem is found, repair as necessary. Was a problem found? — Verify repair Go to Step 9 9 1. Check items that can cause an engine to run lean (long term fuel trim significantly in the positive Diagnostic Aids in DTC P0171 Diagnostic Support. 2. If a problem is found, repair as necessary. Was a problem found? — Verify repair Go to Step 10 |