The following simplified ignition system wiring diagrams include the coil-on-plug (COP) ignition coils, camshaft position sensor, crankshaft position sensor, and the knock sensor circuits.

Applies to the 2002, 2003, 2004, 2005 4.2L Chevrolet Envoy and GMC Envoy.

DIAGRAM 1: Ignition System (Part 1 of 3)

PART 1 Of 3: Typical Ignition System Wiring Diagram -2002, 2003, 2004, 2005 4.2L Chevrolet TrailBlazer And GMC Envoy

NOTE: The following tutorial will help you test the ignition coils: How To Test The Ignition Coils (2002-2005 4.2L Chevrolet TrailBlazer).

DIAGRAM 2: Ignition System (Part 2 of 3)

PART 2 Of 3: Typical Ignition System Wiring Diagram -2002, 2003, 2004, 2005 4.2L Chevrolet TrailBlazer And GMC Envoy