GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 Aveo 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Electronic Ignition (EI) System Diagnosis

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

Ignition voltage is supplied to the ignition coil assembly. The engine control module (ECM) provides a ground for the ignition control (IC) 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.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electronic Ignition (EI) System Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

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

  1. Ignition OFF for 1 minute, disconnect the harness connector at the ignition coil.
  2. Test for less than 5 Ω between the ground circuit terminal B and ground.
    3. ⇒If greater than the specified range, repair the ground circuit for an open/high resistance.
  3. Test for less than 5 Ω between the low reference circuit terminal C and ground.
    4. ⇒If greater than the specified range, test the circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Test for less than 2 Ω between the ignition voltage circuit terminal A and the fuse.
    5. ⇒If greater than the specified range, repair the ignition voltage circuit for high resistance.
  5. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal A and ground.
    6. ⇒If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition voltage circuit fuse is open, test all components connected to the ignition voltage circuit and replace as necessary.
  6. If all circuits test normal, test or replace the ignition coil assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Ignition Coil Replacement
    •  Control Module References for ECM replacement, setup, and programming