There are 2 stored owner reports matching the brakes leading-label group for the 2001 Audi S4 in our NHTSA-sourced dataset. These are unverified consumer reports and may not reflect confirmed defects.
This group counts stored reports whose component label starts with one of this site's matching prefixes, ignoring case. Each matching report counts once within the group. Components mentioned later in the label or only in the narrative are not searched. How component counts work
Loaded 2 of 2 matching reports.
Open the full vehicle complaint log (all categories)BRAKE BOOSTER CHECK VALVE FAILS CAUSING VAC HOSE FEEDING TO BOOSTER UNIT TO BECOME TOTALLY SEPARATED FROM VALVE. RESULT IS NO BRAKE ASSIST. THIS HAPPENED TO ME IN MY 2001 AUDI S4!!!! AT HIGHWAY SPEED! *JB
1) CAR IS 2001 AUDI S4 AVANT. CAR WAS RUNNING FOR APPROXIMATELY 15 MINUTES, AND WAS IDLING AT TOP OF DRIVEWAY FOR ABOUT 5 MINUTES WITH PARKING BRAKE ENGAGED WHILE OTHER CAR IN FRONT WAS BEING MOVED. UPON RELEASE OF PARKING BRAKE REGULAR BRAKES FAILED, RESULTING IN CAR ROLLING DOWNHILL, ABOUT 30 FEET, FROM A STANDING START AND COLLIDING WITH A PARKED CAR. BRAKE PEDAL SHOWED NO RESISTANCE OTHER THAN MILD SPRING PUSH-BACK, AND WAS PUSHED DOWN TO FLOOR. A BRAKE PEDAL WAS PUMPED WITH NO RESULT. SAME BRAKE CONDITIONS WERE REPEATED IMMEDIATELY AFTER COLLISION AND OVER A CONTINUING PERIOD OF MINUTES WITH IDENTICAL RESULTS, DURING WHICH TIME I EXITED AND RETURNED TO CAR ON MULTIPLE OCCASIONS. FINALLY, AFTER APPROXIMATELY 5 MINUTES FOLLOWING THE ACCIDENT BRAKES RESUMED FULL AND NORMAL FUNCTIONING. CAR WAS IDLING THROUGHOUT THIS TIME PERIOD WITHOUT INTERRUPTION. AIR BAGS DID NOT DEPLOY . 3) REPORTED TO DEALER MOHEGAN LAKE MOTORS) ON 1/16 AND TO AUDI AMERICA ON SAME OR NEXT DAY. CAR TOWED TO DEALER ON 1/17. AUDI AMERICA REPORTED LATER THAT THEY HAD NO KNOWLEDGE OF ANY SIMILAR OCCURRENCES OR ISSUES CONCERNING BRAKES - ALSO BEGAN INQUIRY ON WHY AIR BAGS DID NOT DEPLOY , BUT I DID NOT PURSUE THIS DURING OUR DISCUSSIONS SINCE THERE WERE NO INJURIES. DEALER REPORTED ON 1/24 THAT THEY WERE UNABLE TO DUPLICATE THE PROBLEM, AND HAD NO ANSWER FOR THE BRAKE FAILURE, AND WERE TAKING NO CORRECTIVE ACTIONS. AUDI AMERICA REPORTED ON 1/25 THEY WERE TAKING NO FURTHER ACTION AND MAKING NO FURTHER INQUIRIES. *AK
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
NHTSA source checks for this vehicle year
Checks are recorded separately for each dataset, not for the whole page. Dates use UTC. A missing check date does not mean no records exist.
Vehicle import recorded: Apr 28, 2026. This is the stored import date, not confirmation that every source was successfully refreshed.