Chevrolet Sonic Repair Manual: Brake Warning System Description and Operation

Brake Warning Indicator

Brake Warning Block Diagram

B80Park Brake SwitchB20Brake Fluid Level SwitchK9Body Control ModuleP16Instrument Cluster

Hard-Wired

Serial Data

B80 Park Brake Switch

B20 Brake Fluid Level Switch

K9 Body Control Module

P16 Instrument Cluster

(HW)	Hard-Wired
(HW)	Hard-Wired
(DA)	Serial Data
(B80)	B80 Park Brake Switch
(B20)	B20 Brake Fluid Level Switch
(K9)	K9 Body Control Module
(P16)	P16 Instrument Cluster

The instrument cluster turns the brake warning indicator ON when the following occurs:

• The instrument cluster performs the bulb check. The brake warning indicator illuminates for 5 s.
• When the Electronic Brake Control Module (EBCM) detects low brake fluid level it sends a serial data message to the instrument cluster, which will illuminate the red brake indicator.
• The Body Control Module (BCM) detects that the parking brake is engaged. The instrument cluster receives a serial data message from the BCM requesting illumination.

Driver Information Center Messages

When the Electronic Brake Control Module (EBCM) detects low brake fluid level it sets DTC C0267 and sends a serial data message to the Driver Information Center , which will display Brake Fluid Low message.