Cranking Signal: Description and Operation

Circuit Diagram:

PURPOSE
To supply the Engine Control Module (ECM) with an electrical (Input) signal as the engine is being cranked over during engine start.

OPERATION
Battery voltage flows from ignition switch terminal No.4 (during cranking) through the fuse box to ECM pin No.43. This signal allows the ECM to make the appropriate adjustments to its (output) signals such as ignition timing, idle speed control, fuel enrichment, etc; which results in improved engine starts during various operating conditions.