Park Assist Switch - Operation

OPERATION

The status of the park assist switch is continually monitored by the circuitry within the upper instrument panel switch pod. The switch pod receives battery voltage at all times on a fused battery feed circuit, and a path to ground at all times through the instrument panel wire harness. The inputs to and outputs from the switch pod consist of electronic communication with the instrument cluster, also known as the Cab Compartment Node (CCN) over the single wire Local Interface Network (LIN) data bus.

Each time the park assist switch push button is depressed the switch pod circuitry sends an electronic park assist switch status message input to the CCN over the LIN data bus. The CCN then sends an electronic park assist switch request message to the park assist module over the Controller Area Network (CAN) data bus. The park assist module responds to each park assist switch request message by toggling the status of the park assist system from enabled to disabled, or from disabled to enabled, then sends an electronic park assist system status message back to the CCN over the CAN data bus as confirmation.

The CCN responds to the system status message by sending a message to the switch pod over the LIN data bus to control the park assist switch Light Emitting Diode (LED) unit so that the LED is illuminated with the system disabled and the ignition switch in the ON or START positions, and is extinguished with the system enabled or with the ignition switch in any position except ON or START.

The hard wired circuits between components related to the park assist switch may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic controls or communication between modules and other devices that provide some features of the park assist system. The most reliable, efficient, and accurate means to diagnose the park assist switch or the electronic controls and communication related to park assist switch operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.