"service Brake Booster"

[msilvaj12j12]

I changed the alternator on my 2003 chevy tahoe. After I did so i get a message on the DIC "SERVICE BRAKE BOOSTER". Why did this happen? I havent had a single issue regarding the brakes. I also have an issue when I am driving and sometimes the voltage drops and the blower for the vents and the lights dim and then come back on full power. What is going on?

[jro909]

had this problem, check your power steering fluid level...it tripped mine once and the other time required a software update...

[redvett]

No Tahoe's or LD #1500 series trucks have no hydro-boost so checking the PS fluid is not needed. The OP should use a DVO meter and check the output of the alternator and do a load test on the battery. The SBS is a notice the the booster has low vacuum and this could be caused by low voltage since the booster has a vacuum pump mounted on the booster, this supplements the vacuum needed to operate the brakes.