Component Tests and General Diagnostics

CIRCUIT DESCRIPTION
The electronic ignition system uses an individual ignition coil for each cylinder. The powertrain control module (PCM) controls the ignition operation through eight individual ignition control (IC) circuits. Each bank of tour ignition coils is connected to the PCM, power, or ground by the following circuits:
^ Low reference
^ Chassis ground
^ Ignition 1 voltage
^ The appropriate IC circuit

The PCM triggers an ignition coil by grounding the appropriate IC circuit using information from the crankshaft position (CKP) and camshaft position (CMP) sensors.

DIAGNOSTIC AIDS

IMPORTANT:
^ Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets if you diagnose or replace the PCM. Verify that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
^ For any test that requires probing the PCM or component harness connectors, use the Connector Test Adapter kit J 35616-A. Using this kit prevents any damage to the harness connector terminals. Refer to Using Connector Test Adapters in Diagnostic Aids.

Using the Freeze Frame/Failure Records may aid in locating an intermittent condition. If you cannot duplicate the condition, the information included in the Freeze Frame/Failure Records can help determine how many miles were driven since the condition occurred. Operate vehicle within the same Freeze Frame conditions which failed the test in the previous ignition cycle.

Inspect for the following conditions:
^ The load
^ The RPM
^ The temperature

For an intermittent condition, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-4:

Steps 5-15:

Steps 16-23:

The numbers below refer to the step numbers on the diagnostic table.
3. Monitoring the Misfire Current Counters determines if a fault is present.
4. A good indication that the fuse is open is more than 2 of the Misfire Current Counters are incrementing on one side of the engine. Inspect the ignition 1 voltage circuit for a grounded circuit.
8. If the fuse is open and no condition can be found with the ignition coil module circuits, inspect the injector circuits for being grounded.