This bulletin applies to 2012-2013 Buick Regal models equipped with eAssist. A buzz or hum may be heard in the right front, possibly when turning or driving straight. The ABS MIL may be on or Service Brake Assist message may be displayed. DTCs C027B or C0040 may be stored.
The forward lamp harness may be contacting the crank pulley, air conditioning compressor pulley or accessory drive belt due to misrouting or not being secured properly.
Repair wiring as needed or replace the forward lamp harness, correct routing and secure. Once wiring repairs are complete, confirm proper brake booster vacuum pump operation. The pump can be commanded on using GDS2.