System Diagnosis - Crank Signal

Crank Signal Diagnosis:

Crank Signal:

Circuit Description:
Crank signal is ignition voltage signal to the ECM during cranking to allow enrichment and cancel diagnostics until engine is running or 12 volts is no longer on circuit.


Test Description:
Numbers below refer to circled numbers on the diagnostic chart.

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

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