Gap Up/Down Switch

WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

The gap up/down switch allows the driver to determine how closely the adaptive cruise control (ACC) vehicle follows a target vehicle while ACC is engaged. When the ACC vehicle speed is being limited due to a slower travelling vehicle, the ACC vehicle speed is automatically controlled to the follow speed limit. The gap switch has 6 following distance selections that range from 1-2 seconds. The gap switch following distance between the ACC vehicle and the target vehicle is expressed in time as opposed to actual distance. The distance maintained for a selected gap will vary based on vehicle speed. The faster the vehicle speed, the further back you will follow. The gap setting can only be adjusted when the ACC System is engaged. The gap up/down switch is hard-wired to the instrument panel module (IPM) and voltage is provided to the switch from the IPM via the gap up/down ignition 1 voltage circuit. Based on voltage variations, the IPM is able to read the selected gap up/down switch selection and communicates the switch status on the GMLAN serial data circuit to the distance sensing cruise control (DSCC) module. The gap up/down switch is a 3 position momentary switch-Center, Gap Up and Gap Down-with the following valid signal values:

No Activation
Increase Gap
Decrease Gap

The initial push of the gap switch recalls the current setting and activates the display. Subsequent pushes of the gap switch will change the gap setting. Momentarily pressing the gap up/down switch will adjust the switch to the desired gap setting. When the voltage from the gap up/down switch circuit is in an invalid range, the IPM will default to increasing the gap value.