Cirrus L4-2.4L VIN X (1998)
Cruise Control Vacuum Reservoir: Description and Operation
SYSTEM OPERATION
The 4 speed automatic Transmission Control Module (TCM) supplies the speed input to the PCM. The PCM determines acceleration rates. The
speed control software in the PCM uses vehicle speed and acceleration to control to the set speed.
Vehicles with a 3 speed automatic or manual transmission have a vehicle speed sensor (VSS) mounted to an adapter near the transmission output
shaft. The sensor is driven through the adapter by a speedometer pinion gear. The VSS pulse signal is monitored by the PCM to determine vehicle
speed and to maintain speed control set speed. Refer to the appropriate Powertrain Management/Computer and Control Systems/Test Procedures
of this component.