C 1500 Truck 2WD V8-350 5.7L (1989)
Wiring Diagram For Chart C-1B - Crank Signal Diagnosis
CHART C-1B - CRANK SIGNAL DIAGNOSIS
Circuit Description:
Crank signal is a 12 volts 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" of ECM. Test light should be "ON" during cranking and then go "OFF" when engine is
running.
2.
Checks to determine if source of or fuse link was a faulty ECM.
