Engine Controls - Tests W/Codes - Testing: Self-Diagnostics

CAUTION: Ensure ignition is off before disconnecting harness connector from any component or control module. If ECM replacement is recommended in following testing, always ensure ECM connectors and ground circuits are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction.

NOTE: For identification of circuits, terminals and wire colors referenced in the following testing, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article. Always perform applicable drive cycle test after repair is performed to verify if DTC is reset.

NOTE: For following tests, use of New Generation Star (NGS) tester is recommended. NGS tester is referred to as scan tool. For more information, see TESTS W/CODES - INTRODUCTION article.