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 coils consist of the following circuits:

The mounting bracket for the coil assembly provides the ground for the ignition coils. Ensure the mounting bolts are torqued to the correct specification. Refer to Fastener Tightening Specifications .

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Description and Operation

Electronic Ignition (EI) System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. Ignition OFF, disconnect the harness connector at the ignition coil.
2. Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit and ground.

⇒	If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition 1 voltage circuit fuse is open, test all components connected to the ignition 1 voltage circuit and replace as necessary.

Important: Set the DMM to the AC Hertz scale for this test.

3. Connect a DMM between the appropriate ignition control circuit and ground.
4. While cranking the engine, test for more than 20 hertz between the appropriate ignition control circuit and ground.

⇒	If less than the specified range, test the ignition control circuit for a short to voltage, short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.