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
The ignition system uses individual ignition coil/module assemblies for each cylinder. The engine control module (ECM) controls the individual coils by transmitting timing pulses on the ignition control (IC) circuit of each ignition coil/module to enable a spark event. Each ignition coil/module has the following circuits:
Diagnostic Aids
| • | Depending on the location in the spliced ignition voltage circuit, a slight to moderate resistance can cause a misfire or a crank/no start concern. |
| • | Extended engine cranking time, will foul the spark plugs with excessive fuel and cause a crank/no start condition. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference (Except Opel Gt)
| • | Testing for Intermittent Conditions and Poor Connections |
Scan Tool Reference
Control Module References for scan tool information
Special Tools
Circuit/system Verification
Important: Verify that the engine is in good mechanical condition before continuing with this diagnostic.
| • | Review the ignition system specifications and the spark plug inspection procedure to verify the following: |
| - | The ignition coil/modules are correctly connected |
| - | The proper spark plug type |
| - | The proper spark plug gap and torque |
| - | Refer to Ignition System Specifications and Spark Plug Inspection . |
| • | If the engine will start, then observe the scan tool Misfire Current Cylinder parameters. This will indicate the affected ignition coil/modules. |
Circuit/system Testing
- Ignition OFF, disconnect the harness connector at the affected ignition coil/modules.
- Ignition OFF for 90 seconds, test for less than 5 ohms between the ground circuit terminal 1 and ground.
- Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 2 and ground.
- Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 4 and ground.
- Exchange the affected ignition coil/module with the ignition coil/module of a good cylinder.
- Start the engine, observe the scan tool Misfire Current Cylinder parameters.
Component Testing
Use the J 26792 to verify the output of each ignition coil/module.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Ignition Coil Replacement |
