Chart 3 Ignition Control Check

Diagnostic Chart:

Ignition Circuit:

CIRCUIT DESCRIPTION
The Ignition Control Check verifies that the IGNITION CONTROL and BYPASS circuits between the Powertrain Control Module (PCM) and Ignition Control Module (ICM) are functioning properly. This chart requires J39200 voltmeter and J35616 jumper kit.

NOTES ON FAULT TREE
1. CKT 424 is the BYPASS circuit and should be low at key "ON."
2. CKT 423 is the IGNITION CONTROL and Electronic Spark Timing (EST) circuit and should be low with the ICM not receiving crankshaft position sensor pulses.
3. CKT 424, BYPASS circuit, should be high with engine running.