This bulletin applies to 2014-2019 Chevy Silverado vehicles. Some owners may comment of a Service Trailer Brake message on the DIC. When checking for DTCs, a U0415 (Invalid data Received from Electronic Brake Control Module) may be set in the chassis control module. It may be noticed that this message occurs during hard braking, acceleration and/or turns.
This concern could be caused by the brake fluid level near the minimum level. The brake fluid level sensor may momentarily signal the brake fluid level is low as the brake fluid sloshes in the master cylinder reservoir during hard braking, acceleration or turns. The brake fluid level sensor is a direct input to the EBCM. The EBCM sends the brake fluid level data to the chassis control module via the high-speed LAN communication bus. When the chassis control module receives the message that the brake fluid level is low, it sets U0415 and commands the “Service Trailer Brake” message on. The brake fluid level sensor data can be monitored using the scan tool GDS2 under the EBCM antilock braking data list parameter “Brake Fluid Level Sensor”. It will display either “OK” or “Low.”
Fill the master cylinder brake fluid reservoir to the maximum level.
