ENGINE CONTROLS - SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline: Summary

If no Diagnostic Trouble Codes (DTCs) are present and a no-start condition exists, proceed to NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 8.1L AVALANCHE, SIERRA, SILVERADO, SUBURBAN & YUKON XL article. If no DTCs are present and a driveability condition exists, diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.). See SYMPTOMS in TROUBLE SHOOTING - NO CODES - 4.8L, 5.3L & 6.0L "C", "G", "H", "K" & "N" SERIES - FLEX FUEL & GASOLINE article.