Circuit/System Description

WARNING: This page is about a different car, the 2017 Chevrolet Suburban 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.

The instrument cluster illuminates the hill descent indicator and hill descent control off indicator for 5 s after the ignition is turned ON. When the electronic brake control module detects a fault it sends a serial data message to the instrument cluster commanding the hill descent control indicator ON.

The body control module (BCM) monitors the signal circuit from the hill descent control switch. The hill descent switch is a momentary switch that is normally open. When the hill descent control switch is pressed once, the body control module will request the electronic brake control module via serial data to disable or enable the hill descent control. When activated, the switch grounds the hill descent control system signal circuit. The electronic brake control module then enables or disables the hill descent control system. The electronic brake control module will request the instrument cluster via serial data to turn the hill descent indicator ON or OFF to notify the driver.

An intermittent fault in the controller area network (CAN) circuits will cause DTC P155D to set.