2018 GMC Sierra 3500HD

What owners should know

Covers 2015–2019 · 6.6L Duramax diesel (LML 2015–2016, L5P 2017–2019) and 6.0L V8 gas · Updated 2026-10-01

Researched from owner forums and NHTSA complaints and written by Know Your Truck. These are patterns in what owners report, not a guarantee about any particular truck.

Common failures & how to fix them

Parts and video buttons search for your 2018 GMC Sierra 3500HD. Always confirm a part fits using your VIN. Brakes, steering, fuel and airbag work affects your safety, so if you're not sure, have a qualified mechanic do it.

• 2015–2016 Duramax fuel pump (CP4) failure

  Best left to a shop

  Signs: Sudden stalling or no-start, low fuel pressure codes such as P0087.

  Fix: Prevention: change the fuel filter on schedule and buy fuel from busy stations. Some owners replace the CP4 with a different pump design as prevention. A failed pump usually means a full fuel system replacement at a diesel shop.

  Shop: Duramax fuel filterShop: Duramax CP3 conversion kit▶ How-to videos

• Loose brake pedal (2015–2016)

  Dealer (recall)

  Signs: The brake pedal feels loose or doesn't work right.

  Fix: Covered by GM recalls for the brake pedal pivot nut.

  May be covered free by recall 16V069000 / 18V578000. Check the VIN at nhtsa.gov/recalls.

• Block heater cord fire risk (2017–2019 diesels)

  Dealer (recall)

  Signs: A burnt or melted block heater cord or plug.

  Fix: Covered by GM recalls. Don't use the block heater until it's checked.

  May be covered free by recall 19V328000 / 21V496000. Check the VIN at nhtsa.gov/recalls.

• 'Service trailer brake system' warning

  Easy DIY

  Signs: Trailer brake warnings that cut the trailer brakes while towing.

  Fix: Start with the simple things: clean and inspect the 7-pin trailer connector and the trailer's wiring. If it continues, have a dealer check the trailer brake module.

  Shop: 7 pin trailer connector▶ How-to videos

• L5P cracked intercooler pipe

  Easy DIY

  Signs: A loud pop, then low power and limp mode.

  Fix: Replace the plastic charge pipe. Many owners upgrade to a metal pipe.

  Shop: L5P Duramax intercooler pipe▶ How-to videos

Recalls

A recall doesn't mean a truck still has the problem. Enter the truck's VIN at nhtsa.gov/recalls or ask a dealer to see whether the repair was done.

• Air Bags:Side/Window:Curtain:Inflator

  Oct 2024 · #24V756000

  General Motors, LLC (GM) is recalling certain 2018 Chevrolet Silverado 1500, GMC Sierra 1500, 2018-2019 Chevrolet Silverado 2500, 3500, and GMC Sierra 2500, 3500 Crew Cab trucks. The left or right-side roof-rail air bag (RRAB) inflator end cap may detach from the inflator or the inflator sidewall may rupture.

  Risk and fix

  Risk: A separated inflator end cap or inflator rupture can allow compressed gas to escape, resulting in the end cap or other components being propelled into the vehicle, increasing the risk of injury or crash.

  Fix: Dealers will replace the left and right side RRAB modules, free of charge. Owner notification letters were mailed November 8, 2024. Owners may contact Chevrolet customer service at 1-800-222-1020, and GMC Customer Service at 888-988-7267. GM's number for this recall is N242474500.

• Fuel System, Diesel:Storage:Tank Assembly

  Feb 2023 · #23V047000

  General Motors, LLC (GM) is recalling certain 2017-2019 Chevrolet Silverado 2500, 3500, and GMC Sierra 2500, 3500 vehicles equipped with a dual fuel tank option. The rear fuel tank may collapse and prevent the fuel pump from transferring fuel to the front tank, resulting in an engine stall.

  Risk and fix

  Risk: An engine stall increases the risk of a crash.

  Fix: Dealers will inspect the fuel tank and fuel pump module, replacing them as necessary. Dealers will also add a vent hose to the rear tank assembly. Repairs will be performed free of charge. An interim owner notification letter informing owners of the safety risk was mailed on March 15, 2023. Owner notification letters were mailed June 21, 2023. Owners may contact Chevrolet customer service at 1-800-222-1020 or GMC customer service at 1-800-462-8782. GM's number for this recall is N222368030.

• Equipment:Electrical:Engine Block Heater

  Jul 2021 · #21V496000

  General Motors, LLC (GM) is recalling certain 2017-2019 Chevrolet Silverado 2500, 3500 and 2017-2019 GMC Sierra 2500 and 3500 vehicles equipped with a Duramax diesel 6.6 liter engine and an optional engine-block heater cord. An electrical short-circuit may occur in the engine-block heater cable or in the terminals that connect the heater cable to the block heater.

  Risk and fix

  Risk: An electrical short-circuit can increase the risk of a fire.

  Fix: Dealers will replace engine block heaters and heater cords. Vehicles that have this feature disabled as a remedy to the safety condition will be contacted and offered replacement block heaters and heater cords under a separate customer satisfaction program, free of charge. GM will provide free replacement block heaters and cords under a separate customer satisfaction campaign. For vehicles previously included in recall 19V-328, the heater cord will be replaced and rerouted, free of charge. Interim owner notifications were mailed on August 13, 2021. Owner notification letters are expected to be mailed on April 4, 2022. Customers may call GMC customer service at 1-800-462-8782. GM's number for this recall is 212329840.

• Engine

  Apr 2019 · #19V328000

  General Motors LLC (GM) is recalling certain 2019 Chevrolet Silverado 4500, 5500 and 6500 vehicles and 2017-2019 Chevrolet Silverado 2500 and 3500 vehicles and GMC Sierra 2500 and 3500 vehicles equipped with Duramax 6.6 liter diesel engines and an optional engine-block heater. The engine block heater cord or the terminals that connect the heater cord to the block heater may short circuit and fail.

  Risk and fix

  Risk: A short-circuit may damage the engine components and increase the risk of fire.

  Fix: GM will contact owners, dealers will replace the engine block heater, free of charge. Additionally, in Chevrolet Silverado 2500 and 3500 vehicles, dealers will install a new rerouted heater cord. The recall began December 11, 2019. Owners may contact GM customer service at 1-586-596-1733. GM's number for this recall is N182206310.

• Fuel System, Gasoline:Storage:Tank Assembly

  Feb 2019 · #19V088000

  General Motors, LLC (GM) is recalling certain 2016-2018 GMC Sierra 3500 and Chevrolet Silverado 3500 trucks equipped with gasoline engines and dual fuel tanks. The fuel-level sensor in the front tank may stick in a low-level position, allowing the rear tank to overfill the front tank.

  Risk and fix

  Risk: If the front tank overfills, the excess pressure may cause the front tank to expand and contact the driveshaft, possibly resulting in a hole in the tank. The hole will leak fuel, which in the presence of an ignition source, can increase the risk of a fire.

  Fix: GM has notified owners, and dealers will replace the rear-tank fuel-pump module, inspect the front tank and, if necessary, replace the front tank, free of charge. The recall began July 30, 2019. GM's number for this recall is N182204190.

• Seat Belts:Front:Retractor

  Sep 2017 · #17V567000

  General Motors (GM) is recalling certain 2017-2018 Chevrolet Silverado 2500 and 3500 and GMC Sierra 2500 and 3500 trucks. The front seat belt retractor assemblies were built with the incorrect torsion bar. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 209, "Seat Belt Assemblies."

  Risk and fix

  Risk: The seat belt retractors may not perform as intended during a crash, increasing the risk of injury.

  Fix: GM will notify owners, and dealers will replace both front seat belt retractor assemblies, free of charge. The recall began March 24, 2021. Owners may contact GMC customer service at 1-888-988-7267 or Chevrolet customer service at 1-800-222-1020. GM's numbers for this recall are 17368, 17375, and 17376.

Owner complaints by area

Reports owners filed with NHTSA. They aren't verified, and one complaint can mention more than one area. Tap an area to read the most recent ones.

• Service Brakes6

  • Filed Dec 2025

    Driving on the freeway going approx 70 MPH and the ABS warning light, and Stabilitrak warning light suddenly turned on. I’m sure you can imagine how panicked I was going that fast on the freeway and having my brake warnings suddenly turn on. Especially with my entire family in the vehicle with me at the time. Could feel a difference when I was attempting to brake and exit the freeway. Had to apply tons of pressure to get the brake pedal to engage. The cruise control would no longer work, and the trailer brake monitoring system also began flashing. Truck has been to 2 GMC dealerships the ABS module was replaced made it approximately 2 miles and it came back on. Truck is currently waiting for another part to attempt to fix the problem. Truck has 86,000 miles on it.

  • Filed Jul 2022

    A persistent, very distracting alert saying "service trailer brakes"

  • Filed Mar 2022

    The contact owns a 2018 GMC Sierra 3500. The contact stated after driving on a long downhill road at an undisclosed speed with his 2017 Highland Ridge 349 RV hooked to the vehicle, as he was reaching a leveling point and depressing the brake pedal to slow the vehicle, the brakes failed to operate as needed. The contact stated that as he depressed the brake pedal further, the brake pedal overheated and would no longer respond properly. The contact stated that the vehicle was rated at 22,000-23,000 while the trailer was 14,300 pounds loaded maximum. The contact stated that the trailer currently weighed 11,000 pounds. There were no warning lights illuminated. The contact stated that the failure had been reoccurring while driving. The vehicle was taken to the dealer who informed the contact that the braking system was operating properly. The manufacturer was not notified of the failure. The failure mileage was unknown.

  • Filed Apr 2020

    APRIL 9TH 2020 I WAS OPERATING MY VEHICLE A 2018 GMC SIERRA 3500 DENALI EQUIPPED WITH THE DIESEL PACKAGE. I WAS TOWING A BOBCAT SKID STEER ON A TRAILER WITH A TOTAL WEIGHT OF APPROXIMATELY 4300LBS. I WAS TRAVELING AT ABOUT 45 MPH WHEN I ENCOUNTERED A RED LIGHT. WITH PLENTY OF ROOM TO STOP I APPLIED THE BRAKES AS NORMAL. THEY INITAILLAY GRABBED AND SLOW MY TRAVEL TO ABOUT 40 MPH. THEN OUT OF WHAT SEEMED NOWHERE THE BRAKE PEDAL RAPIDLY WENT TO THE FLOOR AND THE VEHICLE FREEWHEELED THROUGH THE LIGHT. I ATTEMPTED MULTIPLE TIMES TO EASE OFF THE PEDAL AND REAPPLY TO NO AVAIL. UPON ENTERING THE INTERSECTION I NEARLY CRASHED INTO A VEHICLE. WHEN I NEARLY I MEAN WITH INCHES. I IMMEDIATELY SLAMMED THE E-BRAKE BRINGING THE TRUCK TO A SKIDDDING HALT. AFTER DROPPING THE TRAILER OFF IN AN EMPTY PARKING LOT MY VEHICLE WENT TO MY LOCAL DEALER. THE SERVICE ADVISER WHO 1ST ENCOUNTERED THE VEHICLE EXPERIENCED THE ISSUE 1ST HAND.AFTER HAVING IT FOR NEARLY A WEEK THEY CALLED TODAY TO SAY 'THEY CAN'T FIND THE ANY ISSUES'. THAT MAKES THIS SITUATION EVEN MORE DANGEROUS. YOU'RE UNAWARE WHEN THIS CAN HAPPEN. THESE VEHICLES NEED TO HAVE A NEW RECALL IMMEDIATELY

  • Filed Nov 2019

    I WAS DRIVING UP HILL THE TRUCK LOST POWER DIED/SHUTDOWN SO I HAD NO POWER STEERING NO POWER BRAKES WE LIVE ON A COUNTRY RURAL ROAD. HAD THE TRUCK TOWED TO KENDALL CHEVROLET IN EUGENE OREGON WHERE IT HAS BEEN SINCE NOVEMBER 2 WITH ELECTRICAL ISSUES THAT THEY ARE TRYING TO PINPOINT.

  • Showing the 5 most recent of 6.
• Steering3

  • Filed Nov 2019

    I WAS DRIVING UP HILL THE TRUCK LOST POWER DIED/SHUTDOWN SO I HAD NO POWER STEERING NO POWER BRAKES WE LIVE ON A COUNTRY RURAL ROAD. HAD THE TRUCK TOWED TO KENDALL CHEVROLET IN EUGENE OREGON WHERE IT HAS BEEN SINCE NOVEMBER 2 WITH ELECTRICAL ISSUES THAT THEY ARE TRYING TO PINPOINT.

  • Filed Nov 2019

    TL* THE CONTACT OWNS A 2018 GMC SIERRA 3500. WHILE DRIVING APPROXIMATELY 60 MPH AND HAULING A TRAILER, THE ABS, SERVICE TRAILER BRAKE, SERVICE POWER STEERING, AND SERVICE STABILITRAK WARNING INDICATORS ILLUMINATED. ALSO, THE VEHICLE LOST BRAKING FUNCTIONALITY. THE CONTACT ALSO STATED THAT THE FAILURE OCCURRED WHILE NOT TOWING A TRAILER. THE VEHICLE WAS TAKEN TO BUSTER MILES CHEVROLET (1884 ALMON ST, HEFLIN, AL 36264, (256) 781-4536) TO BE DIAGNOSED, BUT THE MECHANIC WAS UNABLE TO RETRIEVE A FAULT CODE. THE CONTACT WAS INFORMED THAT THE FAILURE MAY BE DUE TO A WHEEL SPEED SENSOR. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS INFORMED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 16,068.

  • Filed Mar 2018

    STEERING WHEEL SHAKING FROM 70MPH TO 78 MPH HIGHWAY DRIVING

• Electrical System2

  • Filed Dec 2025

    Driving on the freeway going approx 70 MPH and the ABS warning light, and Stabilitrak warning light suddenly turned on. I’m sure you can imagine how panicked I was going that fast on the freeway and having my brake warnings suddenly turn on. Especially with my entire family in the vehicle with me at the time. Could feel a difference when I was attempting to brake and exit the freeway. Had to apply tons of pressure to get the brake pedal to engage. The cruise control would no longer work, and the trailer brake monitoring system also began flashing. Truck has been to 2 GMC dealerships the ABS module was replaced made it approximately 2 miles and it came back on. Truck is currently waiting for another part to attempt to fix the problem. Truck has 86,000 miles on it.

  • Filed Jul 2024

    The contact owns a 2018 GMC Sierra 3500. The contact stated while driving at various speeds, several unknown warning lights illuminated on the instrument panel. The contact pulled over to the shoulder of the roadway to restart the vehicle. After the vehicle was restarted, the vehicle hesitated to stop while depressing the brake pedal. The local dealer was contacted, but the vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 53,800.

• Exterior Lighting2

  • Filed Feb 2019

    SHAKING OR FLICKERING, HEADLIGHTS WHEN DRIVEN ON ROUGH ROAD SURFACES FLICKER OR SHAKE LIKE BLINKING YOU'RE EYES REAL FAST VERY DISTRACTING FOR MYSELF AND OTHER DRIVERS W.S.P. SAID IT IS A DEFECTIVE EQUIPMENT ISSUE SEND COMPLAINT TO A.G. WA. A.G. IDA. IDAHO ALSO SEND COMPLAINT TO B.B.B. AND N.H.T.S.A. HAD TRUCK IN 4 TIMES FOR REPAIR FOUND PROBLEM BULLETIN NUMBER 18 -NA-001 DOC. ID. 4924668 COMPLAINT TO GMC TALKED WITH 5 TIMES CLOSED MY COMPLAINT 02-06-2019 THERE IS NO FIX FOR THESE HEADLIGHTS. BOUGHT THIS TRUCK NEW 10-17-18 PROBLEM WAS NOTICED DRIVING IT HOME FROM KELLOGG IDA. TO SPOKANE WA. TOOK TRUCK IN AT 536 MILES FOUND PROBLEM TOOK TRUCK HOME IT DIDN'T FIX THE PROBLEM TOOK IT IN AGAIN 659 IT DIDN'T FIX THE TOOK IT IN AGAIN THE THIRD TIME IN AT 822 MILES HAND ME DOCUMENT NO. 4924668 AND INFORMATION NO. 18-NA-001 HEADLAMP SHAKES OR FLICKERS DO NOT FIX. TOOK TRUCK TO DAVE SMITH GMC DEALER IN KELLOGG IDA. FOUND SAME PROBLEM HAD TRUCK 4 DAYS SAME BULLETIN . CMC CLOSES THE CASE WILL LET ME KNOW WHEN AND IF IT CAN BE FIXED IN THE FUTURE SAID IT COULD TAKE YEARS. THANK YOU [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).' *PM

  • Filed Mar 2018

    HID HEADLIGHTS ON MY TRUCK FLICKER SIGNIFICANTLY, AND DIM AND BRIGHTEN, WHILE DRIVING VEHICLE ON BUMPY SURFACES. THIS IS BRAND NEW TRUCK WITH 2500 MILES ON IT. I PAID EXTRA FOR THE ALL TERRAIN VERSION. GMC'S OFFICIAL RESPONSE TO ME IS THAT IT IS NORMAL FOR HID HEADLIGHTS TO FLICKER ON/OFF, AND THEY ARE REFUSING TO DO ANYTHING ABOUT THE ISSUE.

• Fuel System1

  • Filed Apr 2026

    The contact owns a 2018 Gmc Sierra 3500. The contact stated while operating the vehicle at an undisclosed speed the vehicle suddenly shutoff, the vehicle was coasted to side of the road. The contact referenced NHTSA Campaign Number: 21V739000 (FUEL SYSTEM, GASOLINE) however, the VIN was not included in the recall repair. The vehicle was towed to a dealer where it was diagnosed to be the fuel control module. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 177,000.

• Gasoline1

  • Filed Apr 2026

    The contact owns a 2018 Gmc Sierra 3500. The contact stated while operating the vehicle at an undisclosed speed the vehicle suddenly shutoff, the vehicle was coasted to side of the road. The contact referenced NHTSA Campaign Number: 21V739000 (FUEL SYSTEM, GASOLINE) however, the VIN was not included in the recall repair. The vehicle was towed to a dealer where it was diagnosed to be the fuel control module. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 177,000.

• Forward Collision Avoidance1

  • Filed Dec 2025

    Driving on the freeway going approx 70 MPH and the ABS warning light, and Stabilitrak warning light suddenly turned on. I’m sure you can imagine how panicked I was going that fast on the freeway and having my brake warnings suddenly turn on. Especially with my entire family in the vehicle with me at the time. Could feel a difference when I was attempting to brake and exit the freeway. Had to apply tons of pressure to get the brake pedal to engage. The cruise control would no longer work, and the trailer brake monitoring system also began flashing. Truck has been to 2 GMC dealerships the ABS module was replaced made it approximately 2 miles and it came back on. Truck is currently waiting for another part to attempt to fix the problem. Truck has 86,000 miles on it.

• Visibility1

  • Filed Feb 2024

    The contact owns 2018 GMC Sierra 3500. The contacted stated that while the vehicle was parked in the driveway, the vehicle started and the defrost system was activated and the contact's daughter entered the vehicle and saw that it was smoking and informed the contact. When the contact arrived at the vehicle, the rear window had shattered. No warning light was illuminated. The vehicle was not taken to the dealer and was not repaired. The contact referenced GMC Customer Satisfaction Program Number: N192220470 (Faulty Rear Defrost Circuit) as a possible solution however, the VIN was not included in the recall. The manufacturer was not made aware of the failure. The approximate failure mileage was 70,000.

• Visibility/Wiper1

  • Filed Feb 2023

    17Jan2023. 2018 GMC Sierra 3500HD Denali. Northbound on I37 near Three Rivers, TX. Speed approx 75 mph. Temp approx 55F. Wx conditions, 1/2 mile vis in fog. Traffic, zero vehicles ahead, one vehicle approx 100 yards behind. Time approx 0815. No overpasses encountered. Cruise control engaged. My son and I were talking when we both heard a sound us above resembling ripping cloth lasting approx 1/2 second immediately followed by a loud explosion followed by the sound of fragmented clinking. The rush of wind noise followed as we could hear pieces of glass continue be taken by the slipstream. I was able to immediately deduce that the sunroof had catastrophically failed. I never use the sunroof or even open the slider so luckily it was closed as usual and no glass fell into the cab and no injuries were sustained. My son and I began to look around us while continuing down the highway to see if an object could've caused this. With no vehicles in a position to have flung a rock or other material and no overpasses in the area, we concluded it must've been a defect. I took the next exit and stopped in a gas station parking lot. We exited the truck and visually inspected the roof. The glass was indeed shattered. Further, the glass had appeared to failed outward as the remaining glass was directed away from the cab. There had been no prior indications of impending failure. There were no warning lights and the police were not called. Had a vehicle been close behind the outcome may have been worse as it would've been showered with debris. The vehicle is under warranty but GM has declined coverage, claiming it must've been a rock or something, even though that would've been impossible given the circumstances.

• Power Train1

  • Filed Nov 2019

    I WAS DRIVING UP HILL THE TRUCK LOST POWER DIED/SHUTDOWN SO I HAD NO POWER STEERING NO POWER BRAKES WE LIVE ON A COUNTRY RURAL ROAD. HAD THE TRUCK TOWED TO KENDALL CHEVROLET IN EUGENE OREGON WHERE IT HAS BEEN SINCE NOVEMBER 2 WITH ELECTRICAL ISSUES THAT THEY ARE TRYING TO PINPOINT.

• Electronic Stability Control (esc)1

  • Filed Nov 2019

    TL* THE CONTACT OWNS A 2018 GMC SIERRA 3500. WHILE DRIVING APPROXIMATELY 60 MPH AND HAULING A TRAILER, THE ABS, SERVICE TRAILER BRAKE, SERVICE POWER STEERING, AND SERVICE STABILITRAK WARNING INDICATORS ILLUMINATED. ALSO, THE VEHICLE LOST BRAKING FUNCTIONALITY. THE CONTACT ALSO STATED THAT THE FAILURE OCCURRED WHILE NOT TOWING A TRAILER. THE VEHICLE WAS TAKEN TO BUSTER MILES CHEVROLET (1884 ALMON ST, HEFLIN, AL 36264, (256) 781-4536) TO BE DIAGNOSED, BUT THE MECHANIC WAS UNABLE TO RETRIEVE A FAULT CODE. THE CONTACT WAS INFORMED THAT THE FAILURE MAY BE DUE TO A WHEEL SPEED SENSOR. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS INFORMED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 16,068.

• Engine1

  • Filed Oct 2019

    TL* THE CONTACT OWNS A 2018 GMC SIERRA 3500. THE CONTACT RECEIVED NOTIFICATION OF NHTSA CAMPAIGN NUMBER: 19V328000 (ENGINE). THE CONTACT STATED THAT THE MANUFACTURER EXCEEDED A REASONABLE AMOUNT OF TIME FOR THE RECALL REPAIR. ROYAL MOORE BUICK GMC (1380 SE RIVER RD, HILLSBORO, OR 97123, (503) 648-1153) WAS CONTACTED AND CONFIRMED THAT THE PART WAS NOT AVAILABLE. THE MANUFACTURER WAS ALSO CONTACTED AND MADE AWARE OF THE ISSUE. THE CONTACT HAD NOT EXPERIENCED A FAILURE. PARTS DISTRIBUTION DISCONNECT.

Safety ratings

NHTSA 5-Star Safety Ratings from government crash tests. Ratings can differ by cab style and 2WD/4WD.

NHTSA hasn't published star ratings for this truck. Many heavy-duty pickups aren't included in NHTSA's crash-test program, so this doesn't mean the truck is unsafe.