Cranking Signal: Testing and Inspection

Fig. 019 - Wiring Diagram for Chart C-1B Crank Signal. VIN Z:

CHART C-1B

CRANK SIGNAL

4.3L "B/G" SERIES

FUEL INJECTION (TBI)

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

Fig. 018 Chart C-1B Crank Signal:

Test Description:
Step numbers refer to step numbers on diagnostic chart.
1. Checks for normal (cranking) voltage to terminal "C9" of ECM. Test light should be "ON" during cranking.
2. Checks to determine if source of blown fuse was a faulty ECM.