Ignition 1 voltage is supplied to the ignition coil. The engine control module (ECM) provides a ground for the ignition coil (IC) control circuits. When the ECM removes the ground path of the ignition primary coil, the magnetic field produced by the coil collapses. The collapsing magnetic field produces a voltage in the secondary coil which ignites the spark plugs. The sequencing and timing are controlled by the ECM. The ignition coil consist of the following circuits:

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electronic Ignition (EI) System Description

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Important: Do not perform this diagnostic procedure if you were not sent here from a misfire DTC or the Engine Cranks but Does Not Run diagnostic.

1. Ignition OFF, disconnect the harness connector at the ignition coil.
2. Connect a test lamp between the ignition 1 voltage circuit terminal 2 or B and ground.
3. Ignition ON, command the fuel pump relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, repair the ignition 1 voltage circuit for a short to voltage.

⇒	If the test lamp is always OFF, repair the ignition 1 voltage circuit for a short to ground or an open/high resistance. Replace the fuse if necessary.

4. Ignition OFF, test for less than 2 ohms of resistance between the ignition 1 voltage circuit terminal 2 or B and the fuse.

⇒	If greater than the specified range, repair the ignition 1 voltage circuit high resistance.

5. If all circuits/connections test normal, replace the ignition coil.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Ignition Coil Replacement