Owners have filed 24 complaints
about the 2015 GMC Sierra Denali with NHTSA between 2017 and 2025.
The largest single group is the brakes.
Across this model's run it ranks 8 of 14 worst.
The letter says how bad. This says what kind — whether this year drew
an unusual number of complaints, unusually dangerous
ones, or failures that arrived unusually early.
The dashed ring is 50 — the national norm. Further out is worse.
Complaint volume — 54
Against the median year of the GMC Sierra Denali. 50 means typical for this
model; 100 means roughly double.
Severity — 22
4.2% of these complaints
involved a crash, fire, injury or death, against a national rate of
9.7%.
Early failure — 49
29% of failures with a mileage on record happened under
36,000 miles, against a national rate of
29%.
How 2015 compares with every other GMC Sierra Denali
Complaints filed with NHTSA, by model year. Bar colour is the FaultScore grade:
A
B
C
D
F
ungraded
What breaks on a 2015 GMC Sierra Denali
Every complaint is filed against a part. Follow any row for the complaints about that part alone.
Brakes
729.2%
Median failure at 49,000 miles
Transmission & Drivetrain
520.8%
Median failure at 51,400 miles
Electrical System
312.5%
1 crashes, 0 fires · median 22,567 mi
Other & Unspecified
28.3%
Median failure at 54,500 miles
Engine & Cooling
28.3%
Median failure at 46,000 miles
Seats
14.2%
Median failure at 22,567 miles
Fuel & Propulsion
14.2%
Median failure at 160,000 miles
Body & Structure
14.2%
Median failure at 15,000 miles
Steering
14.2%
Median failure at 39,900 miles
Airbags
14.2%
When it fails
Odometer readings owners gave when they filed. About half of all
complaints include one.
1,000 – 9,999 miles
14.8%
10,000 – 24,999 miles
419.0%
25,000 – 49,999 miles
838.1%
50,000 – 74,999 miles
628.6%
75,000 – 99,999 miles
14.8%
150,000+ miles
14.8%
When owners complained
A spike years after the car went on sale usually means a part wearing
out on schedule across the whole fleet — the kind of pattern no single
owner can see from inside their own car.
Jun 2017peak 2Dec 2025
NHTSA investigations into the 2015 GMC Sierra Denali
An investigation is the step before a recall: the agency has seen enough
complaints to look into a pattern itself. An open one means it thinks
something may be wrong and nothing has been fixed yet.
From 2000 through 2017, Takata produced millions of air bag inflators using two types of phase-stabilized ammonium nitrate ("PSAN") propellant -- propellant 2004 and propellant 2004L. After prolonged exposure to high temperature cycles and humidity, inflators using propellant 2004 can degrade, causing the propellant to burn too quickly when ignited. The rapid burning can cause the inflator to rupture during deployment, potentially causing serious or even fatal injury to vehicle occupants. See 2016 Blomquist Report at www.nhtsa.gov/sites/nhtsa.gov/files/documents/expert_report-hrblomquist.pdf.C...
Complaints that involved harm
Reports where the owner recorded a crash, a fire, an injury or a death.
at 15,000 milesRandolph, MACrash
ELECTRICAL SYSTEM
TL* THE CONTACT OWNS A 2015 GMC SIERRA DENALI. THE CONTACT STATED THAT THE VEHICLE EXHIBITED NUMEROUS ELECTRICAL FAILURES. THE FAILURE CAUSED THE STEERING WHEEL TO LOCK, THE BRAKE SYSTEM NOT TO ENGAGE, AND THE INSTRUMENT PANEL AND ALL OTHER ELECTRICAL SYSTEMS IN THE VEHICLE NOT TO OPERATE NORMALLY. THE VEHICLE WAS TAKEN TO MARTY'S BUICK GMC (5 COLLECTION WAY, KINGSTON MA, 02364, 781-585-7570) SEVERAL TIMES FOR THE FAILURE. THE CONTACT STATED THAT THE DEALER REPLACED WIRES, BUT THE FAILURE WAS NOT CORRECTED. THE CONTACT DID NOT KNOW THE NAME OF THE WIRES THAT WERE REPLACED. THE CONTACT ALSO STATED THAT THE ELECTRICAL FAILURE ALSO CAUSED A CRASH ON THE ROAD MEDIAN BECAUSE THE STEERING WHEEL LOCKED. THERE WERE NO INJURIES AND A POLICE REPORT WAS NOT FILED. THE VEHICLE WAS TAKEN BACK TO THE DEALER FOR FURTHER INSPECTION. THE MANUFACTURER WAS NOTIFIED. THE VIN WAS NOT AVAILABLE. THE FAILURE MILEAGE WAS 15,000.
NHTSA complaint #11033181 — an unverified report by a vehicle owner.
The most recent complaints
In the owners' own words, exactly as filed with NHTSA.
at 160,000 milesMadison Lake, MN
FUEL SYSTEM, DIESEL
The contact owns a 2015 GMC Sierra 2500 Denali. The contact stated that while driving at 65 MPH, the vehicle lost motive power with the “Engine Power Failure” warning light illuminated. The vehicle was towed to the residence. The vehicle was later towed to an independent mechanic, where it was diagnosed and determined that the fuel system had failed and there were metal shavings in the fuel system. The contact was informed that the fuel system needed to be replaced. The vehicle was not repaired. The dealer was contacted; however, the vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline for assistance. The approximate failure mileage was 160,000.
NHTSA complaint #11702330 — an unverified report by a vehicle owner.
Ponte Verdra, FL
ENGINE AND ENGINE COOLING
See attached document for complaint.
NHTSA complaint #11662568 — an unverified report by a vehicle owner.
Batesburg-Leesville, SC
POWER TRAIN
The contact owns a 2015 GMC Sierra 1500 Denali. The contact stated that while shifting the vehicle from park(P) to drive(D), the vehicle hesitated and then jerked into gear. The contact stated that the entire vehicle was shaking when it jerked into gear. The contact stated that the failure was also occurred while shifting the vehicle into reverse(R). Additionally, the failure occurred while slowing down for a traffic signal. The contact stated that the failure was a constant. The contact stated she had not noticed any warning lights during the failure. The contact had taken the vehicle to a local dealer who advised the contact that there were no open recalls for the transmission on the VIN. The vehicle was not diagnosed. The vehicle was not repaired. The manufacturer was not informed of the failure. The failure mileage was unknown.
NHTSA complaint #11576241 — an unverified report by a vehicle owner.
at 30,000 milesColumbia, TN
SERVICE BRAKES
4 MONTHS AGO THE DISPLAY PORTRAYED A MESSAGE STATING, TRAILER BRAKE WARNING, HAVE SYSTEM CHECKED. SINCE THAT TIME I HAVE ATTEMPTED ON NUMEROUS TO HAVE MY VEHICLE CHECKED. BUT AS OF THIS DATE I HAVE NOT BEEN TO HAVE ANY DEALERSHIP LOOK AT MY VEHICLE. I HAVE BEEN TOLD BY DEALERSHIP THAT THE VEHICLE COMPUTER SHOWS A HISTORY BUT NO CURRENT ERROR CODES, AND THEY CAN NOT WORK ON VEHICLE UNTIL IT HAS CURRENT CODES. SO I HAVE A TRUCK THAT IS DESIGNED TO TOW CARGO/VEHICLE BUT I AM NOT ABLE TO USE MY TRUCK FOR THAT PURPOSE BECAUSE OF THIS WARNING MESSAGE. I HAVE CONTACTED DEALERSHIPS, CUSTOMER SERVICE WITH GMC AND EVEN FILED A COMPLAINT WITH TENNESSEE DEPT OF CONSUMER AFFAIRS, BUT NO ONE WANTS TO HELP WITH MY PROBLEM. I HAVE NOTICED ON THE INTERNET THAT I AM NOT THE ONLY ONE WITH THIS ISSUE. DANGEROUS SITUATION SHOULD SOMEONE USE VEHICLE TOWING. BIGGEST PROBLEM GM DOES NOT WANT TO EVEN ACKNOWLEDGE THAT THEY HAVE A PROBLEM.
NHTSA complaint #11385689 — an unverified report by a vehicle owner.
at 57,000 milesPueblo West, CO
UNKNOWN OR OTHER
AC BLOWS HOT AIR QONT GOLD FREON FOR LONGER THEN WEEK AND HALF AND IS BACK TO HOT AIR..LEAD TO BELIEVE ITS THE AC CONDENSER HAS FAILED
NHTSA complaint #11349982 — an unverified report by a vehicle owner.
at 39,500 milesHuber Heights, OH
SERVICE BRAKES
I WAS BACKING UP AT VERY LOW SPEED THE BRAKE PEDAL GOT VERY HARD AND THE VEHICLE ACTED LIKE IT DID NOT WANT TO STOP I HAD TO KEEP PUSHING EXTREMELY HARD ON TO THE BREAK TO GET THE VEHICLE TO STOP I TRIED IT AGAIN IN DRIVE AND THE VEHICLE DID THIS EXACT SAME THING THIS TIME I NOTICED AFTER PAYING PARTICULAR ATTENTION THAT THE BRAKES WHILE THEY WERE HARD TO PRESS WERE PULSATING SO I HAD TO USE EXTREME LEG PRESSURE TO STOP THE VEHICLE. MY TRUCK HAS ALREADY HAD THE RECALL FOR THE SAME ISSUE EARLIER THIS YEAR. WHEN THIS 1ST HAPPENED IT ALMOST CAUSED ME TO WRECK INTO A FENCE
NHTSA complaint #11308038 — an unverified report by a vehicle owner.
at 3,977 milesMission Hills, CA
POWER TRAIN
TRANSMISSION IS NOT ABLE TO BE FIXED. THREE REPAIRS AND GM CAN'T FIX. TRANSMISSION JERKS, SLIPS, CLUNKS. UNCOMFORABLE TO DRIVE. I AM STUCK WITH SUBPAR VEHICLE. GM HAS BEEN HORRIBLE TO WORK WITH. 17 RECALLS? WHY CANT GM MAKE A SOLID RELIABLE VEHICLE AFTER 100 YEARS IN BUSINESS?
NHTSA complaint #11287131 — an unverified report by a vehicle owner.
at 49,000 milesMarblehead, MA
SERVICE BRAKES
HARD BRAKE PEDAL WITH INCREASED EFFORT NEEDED TO DEPRESS THE BRAKE PEDAL. FEELS LIKE TRUCK WILL NOT STOP. HAD TO HAVE TRUCK TOWED. REPORTED BACK ON 11-24-18 TO NHTSA: ( #1115347). BRAKE VACUUM PUMP WAS REPLACED @ GM DEALER ON 11-14-18, SAME SITUATION HAPPENED AGAIN ON 02-19-19. GM TSB # PIT5361D NEEDS TO BE A RECALL.
NHTSA complaint #11182669 — an unverified report by a vehicle owner.
at 55,000 milesBraintree, VT
POWER TRAIN
WHEN COMING TO A STOP, APPLYING A STEADY AMOUNT OF BRAKE PRESSURE THE TRANSMISSION SHIFTS AND LOSES ALL FORMS OF ENGINE BRAKING CAUSING THE TRUCK TO SPEED UP AND OVERSHOOTS THE STOPSIGN.
NHTSA complaint #11180690 — an unverified report by a vehicle owner.
at 77,000 milesCorona, CA
SERVICE BRAKES
POOR BRAKE PERFORMANCE. THE BRAKE PEDAL GETS STIFF AT A LOW SPEED AND CAUSES THE TRUCK TO NOT BRAKE COMPLETELY
NHTSA complaint #11165041 — an unverified report by a vehicle owner.
at 70,135 milesRussellville, AR
SERVICE BRAKES
FAILURE OF THE BELT DRIVEN VACUUM PUMP WHILE DRIVING CAUSING VERY HARD BRAKING AND ALMOST CAUSED AN ACCIDENT. VACUUM PRESSURE DROPPED OFF AND CAUSED THE PEDAL TO BECOME FIRM. LUCKILY AFTER IT WAS INSPECTED FOR REPAIR THERE WASN'T OIL CONTAMINATION IN THE VACUUM LINE OR BRAKE BOOSTER SO THOSE DID NOT HAVE TO BE REPLACED.
NHTSA complaint #11160832 — an unverified report by a vehicle owner.
at 46,000 milesMarblehead, MA
SERVICE BRAKES
POWER BRAKE VACUUM PUMP ISSUE. LOST BRAKES WHILE DRIVING IN STOP AND GO CITY TRAFFIC. HAD TO HAVE TRUCK TOWED, WAS UNSAFE TO DRIVE DUE TO NO BRAKES.
NHTSA complaint #11153471 — an unverified report by a vehicle owner.
at 47,800 milesDistrict Heights, MD
POWER TRAIN
INTERIOR DASH LIGHTS GOES OUT AND A FEW MINUTES LATER THE ENGINE CUTS OFF WHILE I'M TRYING TO PARK. EACH TIME WHILE I WAS BACKING INTO MY PARKING SPACE. AFTER SITTING FOR ABOUT 30 SECONDS THE LIGHTS DASH BOARD LIGHTS COME BACK ON, THEN I RESTART THE TRUCK. SOMETIMES WHILE DRIVING THE DASH BOARD LIGHT BLINK OF AND ON.
NHTSA complaint #11141357 — an unverified report by a vehicle owner.
at 47,800 milesDistrict Heights, MD
ELECTRICAL SYSTEM
INTERIOR DASH LIGHTS GOES OUT AND A FEW MINUTES LATER THE ENGINE CUTS OFF WHILE I'M TRYING TO PARK. EACH TIME WHILE I WAS BACKING INTO MY PARKING SPACE. AFTER SITTING FOR ABOUT 30 SECONDS THE LIGHTS DASH BOARD LIGHTS COME BACK ON, THEN I RESTART THE TRUCK. SOMETIMES WHILE DRIVING THE DASH BOARD LIGHT BLINK OF AND ON.
NHTSA complaint #11141357 — an unverified report by a vehicle owner.
at 22,567 milesWellington, OH
SEATS
VEHICLE STARTED SHOWING "SERVICE LANE DEPARTURE SYSTEM, SERVICE PARK ASSIST, SERVICE TRAILER BRAKE SYSTEM" ALARMS WHILE DRIVING. UPON TAKING IT TO THE DEALER FOR SERVICE IT WAS FOUND TO HAVE BROKEN WIRING FOR HAPTIC MOTOR FOR DRIVERS SEAT. NOT ONLY DID THIS CAUSE A POSSIBLE SAFETY ISSUE WITH THE LANE DEPARTURE SYSTEM AND TRAILER BRAKE SYSTEM NOT WORKING CORRECTLY, BUT IT ALSO CAUSED A POSSIBLE FIRE CONCERN DUE TO BROKEN WIRING.
NHTSA complaint #11115739 — an unverified report by a vehicle owner.
at 22,567 milesWellington, OH
ELECTRICAL SYSTEM
VEHICLE STARTED SHOWING "SERVICE LANE DEPARTURE SYSTEM, SERVICE PARK ASSIST, SERVICE TRAILER BRAKE SYSTEM" ALARMS WHILE DRIVING. UPON TAKING IT TO THE DEALER FOR SERVICE IT WAS FOUND TO HAVE BROKEN WIRING FOR HAPTIC MOTOR FOR DRIVERS SEAT. NOT ONLY DID THIS CAUSE A POSSIBLE SAFETY ISSUE WITH THE LANE DEPARTURE SYSTEM AND TRAILER BRAKE SYSTEM NOT WORKING CORRECTLY, BUT IT ALSO CAUSED A POSSIBLE FIRE CONCERN DUE TO BROKEN WIRING.
NHTSA complaint #11115739 — an unverified report by a vehicle owner.
at 55,000 milesDallas, TX
POWER TRAIN
STARTING THE VEHICLE I'M PUTTING THE TRUCK IN REVERSE, THE TRUCK LUNGES BACKWARDS. ALSO A VIOLENT JERK OF THE VEHICLE HAPPENS. THIS HAPPENS A MAJORITY OF THE TIME. PUTTING THE VEHICLE INTO GEAR TO DRIVE I HAVE A VIOLENT JERK AND A LOUD NOISE. THE TRUCK DOES NOT LUNGE FORWARD WHEN PLACING THE TRUCK INTO DRIVE. THIS HAPPENS A COUPLE OF TIMES A DAY. THIS IS NOT AN ISOLATED INCIDENT.
NHTSA complaint #11098024 — an unverified report by a vehicle owner.
at 56,000 milesHarlingen, TX
SERVICE BRAKES
HARD BRAKE PEDAL. AT LOW SPEED THE BRAKE PEDAL GETS REALLY HARD AND MAKES IT HARD TO STOP THE TRUCK. PEDAL HAS TO GET PUSHED REALLY HARD TO BARELY STOP FROM HITTING OTHER VEHICLES. ONGOING ISSUE.
NHTSA complaint #11066885 — an unverified report by a vehicle owner.
at 39,900 milesEuless, TX
STEERING
TL* THE CONTACT OWNS A 2015 GMC SIERRA DENALI. WHILE DRIVING APPROXIMATELY 60 MPH, THE STEERING LOST POWER AND THE POWER STEERING WARNING INDICATOR ILLUMINATED. THE VEHICLE WAS TOWED TO THE DEALER (SEWELL BUICK GMC OF DALLAS IN DALLAS, TX, PHONE NUMBER: 214-350-8000) WHERE A DIAGNOSTIC TEST WAS PERFORMED. THE CONTACT WAS NOT GIVEN THE RESULTS OF THE TEST. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE AND OFFERED TO PAY A PERCENTAGE OF THE REPAIR COSTS. THE FAILURE MILEAGE WAS 39,900. *BF UPDATED 8/28/18
NHTSA complaint #11055771 — an unverified report by a vehicle owner.
Coffman Cove, AK
AIR BAGS
2015 GMC SIERRA. CONSUMER WRITES IN REGARDS TO SENSING AND DIAGNOSTIC MODULE SAFETY RECALL. *LD THE CONSUMER REQUESTED TO BE ADVISED OF THE OPTIONS OF HAVING A RECALL COMPLETED ON AN ISLAND. UPDATED 10/16/2017
NHTSA complaint #11029809 — an unverified report by a vehicle owner.
at 15,000 milesRandolph, MACrash
ELECTRICAL SYSTEM
TL* THE CONTACT OWNS A 2015 GMC SIERRA DENALI. THE CONTACT STATED THAT THE VEHICLE EXHIBITED NUMEROUS ELECTRICAL FAILURES. THE FAILURE CAUSED THE STEERING WHEEL TO LOCK, THE BRAKE SYSTEM NOT TO ENGAGE, AND THE INSTRUMENT PANEL AND ALL OTHER ELECTRICAL SYSTEMS IN THE VEHICLE NOT TO OPERATE NORMALLY. THE VEHICLE WAS TAKEN TO MARTY'S BUICK GMC (5 COLLECTION WAY, KINGSTON MA, 02364, 781-585-7570) SEVERAL TIMES FOR THE FAILURE. THE CONTACT STATED THAT THE DEALER REPLACED WIRES, BUT THE FAILURE WAS NOT CORRECTED. THE CONTACT DID NOT KNOW THE NAME OF THE WIRES THAT WERE REPLACED. THE CONTACT ALSO STATED THAT THE ELECTRICAL FAILURE ALSO CAUSED A CRASH ON THE ROAD MEDIAN BECAUSE THE STEERING WHEEL LOCKED. THERE WERE NO INJURIES AND A POLICE REPORT WAS NOT FILED. THE VEHICLE WAS TAKEN BACK TO THE DEALER FOR FURTHER INSPECTION. THE MANUFACTURER WAS NOTIFIED. THE VIN WAS NOT AVAILABLE. THE FAILURE MILEAGE WAS 15,000.
NHTSA complaint #11033181 — an unverified report by a vehicle owner.
at 46,000 milesBIG Spring, TX
ENGINE
MY GMC 2015 DIESEL DURIMAX TRUCK HAD THE ENGINE LIGHT TURN ON AND SAID EMISSION NEEDS SERVICED. IT PROCEEDED TO CUT MY TRAVELING SPEED FROM 75 MPH TO 65 MPH TO 55 MPH. I MADE IT TO DENVER COLORADO BARELY WITHOUT THE TRUCK FALLING TO 4 MPH. I WENT YESTERDAY TO HAVE IT SERVICED. THEY SAID THAT THEY FIXED IT STILL UNDER POWERTRAIN WARRANTY. I DROVE AWAY TO GO BACK TO TEXAS 700 MILES OF HIGHWAY HOME. I DROVE AND THE EXACT SAME PROBLEM HAPPENED AGAIN. I'M WAS ON A HIGHWAY AT THIS POINT WITH HEAVY HIGHSPEED TRAFFIC IN THE MIDDLE OF NOWHERE WHERE THE SPEED LIMIT IS 75 MPH. MY TRUCK SPEED WAS REDUCED BY THE EMISSION SYSTEM AGAIN FROM 75 MPH TO 65 MPH TO 55 MPH. I WAS ALMOST HIT BY A BIG RIG TRUCK WITH MY WIFE IN THE CAR. SOMETIME LATER WERE ALMOST SIDE SWIPED TWICE, AND THEN IT STARTED RAINING AND THE SUN STARTED TO SET, AND MATTERS WENT FROM DANGEROUS TO NEAR DEADLY. WE TRIED TO TURN THE TRUCK AROUND TO GET BACK TO DENVER AND ALMOST WERE HIT AGAIN BECAUSE WITH THE GMC SPEED REDUCTION I COULD NOT ACCELERATE AWAY FROM THE HIGH SPEED CARS COMING AT US. GMC SHUTDOWNS THE CAR SPEED PURPOSELY TO AVOID SOME TINY AMOUNT OF NOX, AND PUT PEOPLE AT RISK OF BEING KILLED ON A HIGHWAY IN RAINY NIGHTIME WEATHER. WE FINALLY MADE IT BACK TO DENVER JUST 19 MILES BEFORE THE TRUCK SPEED WOULD HAVE BEEN REDUCED TO 4 MPH. WE WOULD HAVE TO BEEN ON THAT 75 MPH HIGHWAY RIDING IN THE RIGHT SIDE OF THE SLOW LANE AT 4 MPH !!!!! AT NIGHT IN THE RAIN WITH HIGH SPEED 18 WHEELERS GOING BY AT 75 TO 85 MPH. THE GOVERNMENT AND GMC ARE INSANE TO HAVE DESIGNED THIS, I AM BRINGING IT TOMORROW TO GET TRY TO GET IT FIXED AGAIN BUT THE ORDEAL I WENT THRU IS STILL SCARY AS HELL, AND WORRIED ABOUT IT GETTING FIXED. WE COULD BE KILLED DUE TO THIS. I AM AN ENGINEER DEALING WITH PUBLIC SAFETY, AND I AM IN SHOCK CONCERNING GMC'S AND THE GOVERNMENT OVER STEP IN THIS DESIGN. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).
NHTSA complaint #11002748 — an unverified report by a vehicle owner.
at 52,000 milesHowell, MI
UNKNOWN OR OTHER
BAD WELD ON HVAC CONDENSER. WAITING 7+ WEEKS FOR NATIONAL BACK-ORDERED REPLACEMENT PART. WHY IS THERE NO RECALL SINCE CLEARLY THIS IS A MAJOR SPILL?
NHTSA complaint #10994628 — an unverified report by a vehicle owner.
at 15,000 milesSanford, FL
STRUCTURE:BODY:ROOF AND PILLARS
TL* THE CONTACT OWNS A 2015 GMC SIERRA DENALI. WHILE OPERATING THE VEHICLE, RAIN WATER FROM THE ROOF MOUNTED ANTENNA LEAKED INTO THE PASSENGER SIDE CABIN. THE CONTACT INDICATED THAT THE WATER CAUSED THE ELECTRONICS IN THE VEHICLE TO MALFUNCTION, SUCH AS THE ONSTAR AND NAVIGATION SYSTEM. THE VEHICLE WAS TAKEN TO THE DEALER (RON SONET BUICK/GMC IN LAKE CITY, FLORIDA) WHERE IT WAS DIAGNOSED THAT THE ANTENNA NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE FAILURE MILEAGE WAS 15,000.
NHTSA complaint #10994001 — an unverified report by a vehicle owner.