This service bulletin provides a procedure to add deadener to the batter tray bracket to correct customer concerns of a Service Engine Soon (SES), Reduced Power, Service Brake, Reduced Steering and/or Stabilitrak Message Illuminated on DIC, multiple DTCs.
full bulletin at NHTSA ↗2021 Chevrolet Blazer brakes problems
moderate 17 complaints filed with NHTSA · avg repair $450 · see brakes across all vehicles →
Complaints
17
Recalls
0
Avg fix
$450
What stands out
Of the 4 model years of Chevrolet Blazer we track for brakes problems, this one carries the most owner complaints on file — 17.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering brakes on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This informational bulletin instructs the tech when fuel/fluid is needed to be tested and where it can be sent for analysis.
full bulletin at NHTSA ↗This bulletin advises the dealers to maintain the vehicle stock on hand by doing a full inspection on the vehicles before being sold (prepping) to the customer.
full bulletin at NHTSA ↗This technical bulletin provides repair information to correct a customer concern of hearing front brake grind/groan noise after sitting overnight.
full bulletin at NHTSA ↗This service bulletin provides a procedure to clean the back side of the rims and rotors and to correct the customer concern of wheel clicking.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners describe a spectrum of brake defects in 2021 Chevy Blazers. The most severe are complete brake failures without warning—vacuum pump failure in particular has left owners unable to stop at highway speeds. One owner's failed pump sent shrapnel into the engine, requiring a $10,000 repair bill.
Brake noise starts almost immediately: owners report squealing and grinding at under 400 to 1,000 miles, from brand-new vehicles. Dealerships initially dismiss this as normal due to copper regulations in brake pad material, or refuse to service the vehicle because the noise isn't loud enough yet. One owner was told a repair was under development but no timeline exists; the dealer acknowledged the failure but had no fix available at time of complaint.
Brake pedal stiffness and loss of power assist show up next, with "Brake Assist" warnings on the dash and pedals either locking up or going soft—sometimes all the way to the floor. One owner experienced this at 65 mph on the freeway. A brake booster failure at 50,000 miles created the same symptom.
A low-battery voltage scenario caused complete brake failure in one case, diagnosed only after the fact. The owner also experienced concurrent electrical failures the week before.
Parking brake faults include unwanted engagement at startup and failure to disengage, though dealers find nothing wrong after inspection.
Early brake pad wear requiring replacement at under 1,200 miles compounds these concerns.
Failure modes owners describe
Vacuum pump failure
Vacuum pump fails, eliminating power assist to brake system. Owners report the failure occurred without prior warning lights or diagnostic alerts. One owner reported the failed pump caused shrapnel to project into the engine, resulting in engine damage requiring a $10,000 repair. Another owner noted GM previously recalled vacuum pump failures in 2014–2018 models but 2021 Blazer not yet included.
When: Unknown mileage; owner reports failure after 4 years of use
Symptoms owners cite: Complete loss of brake pressure or ability to stop; Stiff brake pedal with no power assist; No warning lights prior to failure; Engine damage from shrapnel after pump failure
Repairs/costs cited: Engine repair cost owner $10,000; vacuum pump replacement required
Recalls/TSBs owners mention: GM acknowledged vacuum pump failures in 2014–2018 models via recall; 2021 Blazer not yet included in recall campaigns despite similar failure mode
Brake noise (squealing/grinding)
Owners report squealing, screeching, or grinding noises from brakes that begin very early in vehicle ownership (under 1,000 miles reported). One owner was told by dealership this is normal due to federal regulations limiting copper in brake pads; another owner received a similar dismissal. Dealership initially refused to replace pads on one vehicle because noise was not deemed 'bad enough,' only spraying brakes. Noise persists and returns quickly after spraying.
When: As early as 400–700 miles; one owner at 1,000 miles; reported at 50 mph and 40 mph braking speeds
Symptoms owners cite: Squealing noise when braking; Metal-to-metal grinding noise; Noise present from new vehicle or very early ownership; Noise persists after dealership spraying treatment
Repairs/costs cited: One dealership said brake pads needed replacement but were on backorder; another dealership would not authorize replacement without noise severity threshold being met
Recalls/TSBs owners mention: Dealerships attribute to federal regulation changes limiting copper in brake pads; one owner notes dealer awareness of grinding failure but states 'no fix' available, with repair under development but no timeline given
Brake system failure warning and stiff pedal
Brake pedal suddenly becomes extremely stiff and unresponsive during highway driving. Owners report 'Brake Assist' warning light appears coinciding with stiff pedal. One owner described pedal as going 'stiff and wouldn't respond,' while another reported pedal 'went to the floor.' Check engine light accompanies the failure in at least one case.
When: One case at unknown mileage; one case at 50,000 miles (brake booster failure); one case at unknown mileage with earlier rattling/brake noise complaints dating to 2021
Symptoms owners cite: Brake pedal becomes stiff with no power assist or pedal goes soft/to the floor; Brake Assist warning light illuminates; Check engine light illuminates; Difficulty slowing vehicle at highway speeds (65 mph reported); Loss of braking ability or extreme difficulty stopping
Repairs/costs cited: One case diagnosed as brake booster failure requiring replacement; one case attributed to low battery voltage by service center, resolved with battery replacement
Recalls/TSBs owners mention: One owner mentions service bulletins exist for brake assist issues on 2021 Blazer but no recall yet; dealer dismissal of prior brake noise complaints cited as missed diagnostic opportunity
Parking brake engagement fault
Parking brake engages on its own when vehicle is parked on flat surface, or refuses to disengage. One owner reports parking brake remains engaged even at startup on flat surface. Another reports vehicle cannot disengage parking brake when parked on incline.
When: Mileage not reported; incidents ongoing
Symptoms owners cite: Parking brake engages upon starting vehicle on flat surface; Vehicle self-brakes during acceleration with harsh screeching sound; Parking brake will not disengage when parked on incline
Repairs/costs cited: Dealership has found no fault after inspection
Low battery voltage affecting brakes
Service center diagnosed brake failure and loss of power assist as resulting from low battery voltage affecting the brake system. Dealership replaced battery as fix. Owner notes this is a safety defect if vehicle can lose complete braking ability due to battery age.
When: Prior week had other electrical failures (climate control, rear camera); battery issue occurred during low-speed city driving
Symptoms owners cite: Complete brake failure during driving; Brake System Failure message on dashboard; Check Engine light; Other concurrent electrical failures (climate control, rear camera)
Repairs/costs cited: Battery replacement; dealership stated battery replacement every 2 years recommended to prevent recurrence
Synthesized from 17 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
The brakes failed on my SUV as I was driving on a city street. Yes it is available for inspection. Losing my breaks almost caused a collision with the car in front of me but due to the distance between the cars and the low speed at the time, I was able to avoid collision and detour into a parking lot where I cruised to a stop with the help of a parking lot space concrete stop. The problem was…
Had brakes trouble with your 2021 Chevrolet Blazer?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the brakes problem on the 2021 Chevrolet Blazer?
It's a documented issue but not catastrophic. 17 complaints have been filed. Repairs average $450 and most owners catch it before it causes a breakdown.
At what mileage does the brakes typically fail?
Mileage data is limited for this issue. Owners report failures across a wide range, suggesting cause is more about driving conditions and maintenance than mileage alone.
What does it cost to fix?
Independent shops typically charge around $450 for brakes repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to brakes?
No active recalls currently cover brakes issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Chevrolet/Blazer.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.