Module, Vehicle Pedestrian Alert: Operation

The microprocessor in the Vehicle Pedestrian Alert Module (VPAM) uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the Controller Area Network (CAN) data bus. This method of communication is also used for VPAM system diagnosis and testing through the 16-way data link connector located on the driver side lower edge of the instrument panel.

The Body Control Module (BCM) has three hardwired input to the VPAM module:

• Vehicle Speed Output (VSO)
• VPAM Enable, High Side Driver
• VPAM Active, Low Side Driver

The VPAM receives input from the BCM when the vehicle has been shifted into drive or reverse in order to enable the audible warning system. In Drive range, at approximately 22 mph the warning is silenced until the vehicle speed returns to approximately 20 mph. Pre-programmed decision algorithms and calibrations allow the VPAM's microprocessor to determine the appropriate response requested from the hardwired outputs from the BCM to the VPAM, specifically the vehicles output speed.

The VPAM receives battery current on a fused ignition switch output (run-start) circuit through a fuse in the Power Distribution Center (PDC). The module receives ground through a ground circuit and take out of the body wire harness connected to the body sheet metal. These connections allow the module to be operational whenever the ignition switch is in the START or ON positions.

The hard wired circuits between components related to the VPAM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the VPAM or 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 VPAM or the electronic controls and communication related to the pedestrian alert system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.