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 IC control circuits. Each bank of four ignition coils is connected to the PCM, power, or ground by the following circuits:
^ Low Reference
^ Chassis ground
^ Ignition 1 voltage
^ The appropriate IC control circuit

The PCM triggers an ignition coil by grounding the appropriate IC control circuit using information from the Crankshaft Position (CKP) and Camshaft Position (CMP) sensors.

DIAGNOSTIC AIDS

IMPORTANT: A missing CMP sensor may cause a long crank condition.

The CKP signal must be available for the engine to start. The CMP signal is not needed to start and operate the engine. The PCM can determine when a cylinder is on either the firing or exhaust stroke by the 24X signal.

Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.

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

TEST DESCRIPTION

Steps 1-6:

Steps 7-16:

Steps 17-27:

Steps 28-35:

The number below refer to the step number on the diagnostic table.
4. This step is to determine if the fault is in the crank sensor circuit or the ECM 1 ignition 1 voltage circuit.