System Diagnosis - Crank Signal

Crank Signal Diagnosis:

Crank Signal Circuit:

CIRCUIT DESCRIPTION
Crank signal is an ignition voltage signal to the ECM during cranking to allow enrichment and cancel diagnostics until engine is operating with 12 volts no longer on the circuit.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. Checks for normal (cranking) voltage to terminal "C9" of ECM. Test light should be "ON" during cranking and then go "OFF" when engine is operating.

2. Checks to determine if source of open fuse or fuse link was a faulty ECM.