Circuit/System Description

The transmission range switch is an integral part of the transmission control module (TCM). As the gear range selector lever is moved, the state of the starter inhibit circuit may change, causing the circuit to open or close. An open circuit indicates a drive range and a low voltage signal, 0 V, at the body control module (BCM). A closed circuit indicates PARK or NEUTRAL and a high voltage, 12 V, signal at the BCM. The BCM uses the starter inhibit circuit status from the TCM in order to enable starter operation.