Ignition System: Testing and Inspection

Electronic Ignition System Diagnosis

Diagnostic Instructions

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

Circuit/System Description

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

Diagnostic Aids

The following conditions can also set the DTC:

* The MIL indicator flashes when there is an engine misfire.
* If the condition is intermittent, moving the related harnesses and connectors, with the engine operating, while monitoring the appropriate scan tool Misfire Current Cylinder parameter may help to isolate the condition.

Reference Information
Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference

Component Connector End Views Connector End Views By Name
Description and Operation

* Electronic Ignition System Description Electronic Ignition System Description
* Hybrid Modes of Operation Description Hybrid Modes of Operation Description

Electrical Information Reference

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

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Start the engine.
2. Observe the scan tool Cylinder 1-4 Current Misfire Counter parameters. The counters should not be incrementing.
3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the K35 Ignition Coil Module.
2. Test for less than 5 ohm between the ground circuit terminal B and ground.

• If greater than the specified range, repair the ground circuit for an open/high resistance.

3. Ignition OFF and all vehicle systems OFF, it may take up to 2 minutes for all the systems to power down, test for less than 5 ohm between the low reference circuit terminal C and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

4. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal A and ground.

• 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 F9 is open, test all components connected to the ignition voltage circuit and replace as necessary.

5. Engine running, observe the Ignition Coil 1-4 Control Circuit Low Voltage Test Status on the scan tool. Test Status should be Ok or Not Run.

• If test status is Malfunction test for open or short to ground.

6. Engine running, observe the Ignition Coil 1-4 Control Circuit Open Test Status on the scan tool. Test Status should be Ok or Not Run.

• If test status is Malfunction test for open circuit.

7. Engine running, observe the Ignition Coil 1-4 Control Circuit High Voltage Test Status on the scan tool. Test Status should be Ok or Not Run.

• If test status is Malfunction test for short to voltage.

8. If all circuits test normal, test or replace the K35 Ignition Coil Module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Ignition Coil Replacement Service and Repair
* Spark Plug Replacement Service and Repair
* Control Module References Control Module References for replacement, setup, and programming