Complaint volume
290 consumer-submitted complaints are matched to this model year. Treat the count as a research signal, then read the actual summaries for repeated symptoms.
Complaint records
2018 GMC Sierra Complaints
290 consumer-submitted complaints on record for the 2018 GMC Sierra, grouped by component category.
290 Total complaints
10 Crash reports
1 Fire reports
5 Injury reports
Complaint data reflects consumer-submitted reports. A complaint is not proof
of a defect, recall, or manufacturer fault. Enriched severity fields come
from official bulk records when the complaint can be matched by ODI number.
Buyer interpretation
How to use these complaints before buying
Complaint records are most useful when they turn into inspection points, seller questions, and comparison checks against nearby model years.
Pattern to inspect
The most common categories are power train, engine, service brakes. Use those categories as a test-drive checklist instead of judging the vehicle from the total count alone.
Severity flags
Enriched records include 10 crash reports, 1 fire report, 5 injury reports, and 0 fatality reports. These fields come from complaint records and should be read in context.
Mileage clue
Mileage is available on 121 complaints, with an average reported failure mileage of 45,272 miles. Compare that with the mileage on the listing.
Questions to ask the seller
- Have you had any problems related to power train, engine, service brakes?
- Can I see recent maintenance and repair records?
- Has the vehicle ever been towed, involved in a crash, or repaired for the same issue twice?
- Can we also check the recall record for this 2018 GMC Sierra?
Used-car checklist
Use these complaints before the test drive.
Build a buyer checklist to turn these issues into questions and inspection points.
2018 GMC Sierra
Build buyer checklist Compare with other years Sends year, make, and model to pre-fill your checklist.
How severe are the 2018 GMC Sierra complaints?
10 Crash
1 Fire
5 Injury
0 Fatality
12 Towed
3 Medical attention
What are the most common 2018 GMC Sierra complaint categories?
POWER TRAIN 85
ENGINE 30
SERVICE BRAKES 15
UNKNOWN OR OTHER 14
ELECTRICAL SYSTEM 11
ELECTRICAL SYSTEM,SERVICE BRAKES 10
POWER TRAIN,ENGINE 10
STEERING 10
AIR BAGS 6
SEAT BELTS 4
290 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| May 2022 | POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM | I was driving down the highway when my vehicle loss control of operation and check engine light came on. After taking it to the GMC dealership it was determined to be a bad lifter in the motor. The garage had to take the motor completely apart to repair a bent rod and cylinder in the motor. There are numerous reports and a pending class action lawsuit concerning this device in the GMC Sierra trucks and other GMC vehicles. The lifters in the cylinder of this motor are designed to switch the engine from V4 to V6 to save on gasoline. My vehicle has been repaired by the GMC garage but I've seen reports of this problem repeatedly happening in these vehicles and it causes me great concern because if there is a lot of traffic in the area I could get hit or cause an accident by not being able to operate the truck. My vehicle is available for inspection upon request. The safety of myself and others is put at risk because the sudden equipment breakdown could cause an accident. The problem was confirmed by the dealer. No other parties have inspected the vehicle. No warning lamps went off prior to this happening and the vehicle is only a 2018 and only has 36,000 miles on it. | Crash: No Fire: No | Unknown |
| May 2022 | EXTERIOR LIGHTING | The left rear tail light assembly is subject to direct wheel spray resulting in premature corrosion and failure of the lightbulb and wiring harness. Failure first occurred Within 18 months of ownership. I cleaned the contacts and packed the connection with dielectric grease. However after three years the bulb connection is now totally corroded and the circuit has failed requiring harness replacement. The problem is so widespread, replacement wiring harnesses for the left rear tail light assembly are out of stock and unavailable from GM parts. I am now using the vehicle without operating right rear turn signals. GM-trucks.com is an owners chat room with many entries about this problem. [XXX], BSME, P.E. SAE INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6). | Crash: No Fire: No | Unknown |
| Apr 2022 | STEERING | On 2/26/22, approximately 24,000 miles on the vehicle, while traveling on the Interstate a warning popped up in the display that the power steering had failed and to operate the vehicle with caution. Immediately I noticed I had no power steering, and the vehicle was extremely hard to steer. I exited the interstate and turned the vehicle off. I conducted a visual inspection; no issues were immediately apparent. After several minutes I started the vehicle, and the power steering began functioning. I conducted an Internet search and learned this is a common issue for GMC trucks, previously resulting in numerous crashes and over one million vehicles being recalled. NHTSA campaign number: 18V586, GM’s number for the recall 18289. 3/1/22, I contacted GM customer care and was advised my vehicle was not part of the recall. I was advised to take the vehicle to a GM service center, at my cost. 3/1/22, I contacted Mossy GMC of Picayune, MS, and spoke with a technician, who advised the issue is usually due to a drop in voltage and advised me to replace the battery. 3/19/22, replaced the battery. 3/30/22, upon startup the power steering again failed. I turned the vehicle on and off several times, and the power steering began functioning. 3/30/22, went to Mossy of Picayune, spoke with a technician, who advised he was quite familiar with the issue, stating this is a common problem with GMC trucks, he advised to replace the battery. Told him I replaced the battery on 3/19/22, he stated I would likely need to have the steering module reprogrammed, at my expense $130.00, or replace the steering assembly, again at my expense $1,500.00. 4/3/22, while turning the power steering failed, and the vehicle was extremely difficult to steer. I turned the vehicle off and waited several minutes. Upon startup the power steering began functioning. The power steering failure is a MAJOR safety hazard and a recall needs to be issued before someone loses their life. | Crash: No Fire: No | Unknown |
| Mar 2022 | ELECTRICAL SYSTEM,SERVICE BRAKES | “Service- trailer brake system” light keeps coming on. It is super repetitive. It comes on about every 30 seconds. It’s a loud beep that lasts quite a few seconds. Eventually, the beeping did not stop until the truck was stopped. Truck was just bought yesterday. Happens at any speed, even when stopped. | Crash: No Fire: No | Unknown |
| Mar 2022 | SERVICE BRAKES | Yesterday afternoon I heard a beeping noise that was persistent and it said trailer brake check the same alert showed up today making it impossible to drive safely with the alert popping up every min | Crash: No Fire: No | Unknown |
| Feb 2022 | SERVICE BRAKES, HYDRAULIC | The contact owns a 2018 GMC Sierra 1500. The contact stated while driving approximately 35 MPH, the assist brake warning light was illuminated and the contact had to depress the brake pedal to the floor to stop the vehicle. The contact took the vehicle to the local dealer, where it was diagnosed with needing the vacuum pump to be replaced. The vehicle was not repaired but was pending repairs. Upon investigation, the contact associated the failure with NHTSA Campaign Number: 20V603000 (Service Brakes, Hydraulic). The manufacturer had not been informed of the failure. The failure mileage was approximately 37,000. | Crash: No Fire: No | 37,000 |
| Feb 2022 | POWER TRAIN | The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at various speeds, the vehicle experienced shifting while shifting into a lower gear, causing the vehicle to suddenly lurch forward. The cause of the failure was not determined. The local dealer was notified of the failure but no assistance was offered. The manufacturer was not contacted. The failure mileage was 50,000. | Crash: No Fire: No | 50,000 |
| Feb 2022 | POWER TRAIN | Transmission shrudder with low mileage | Crash: No Fire: No | Unknown |
| Jan 2022 | SEAT BELTS | The contact owns a 2018 GMC Sierra 1500. The contact stated that the seat belt straps for the rear driver’s and passenger’s side seats would no longer retract and were stuck between the seat cushions. The cause of the failure was not determined however, the local dealer informed the contact that the seat belt retractors were likely defective and would need to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 60,000. | Crash: No Fire: No | 60,000 |
| Jan 2022 | VISIBILITY/WIPER | When operating my truck two days ago, I smelled something burning. I then noticed a small plume of white smoke coming from the rear driver's side window area. I then noticed my rear defroster was on, which I shut of right of way. About 30 seconds later, I heard a loud pop and I noticed the rear driver's side portion of the window was shattered. I brought my truck to the dealership and they said they could not figure out what happened. I believe it is tied to a prior recall, but they said my truck was found not to have any issues at that time. I believe there is a direct correlation with the recall issued and what happened a couple of days ago. | Crash: No Fire: No | Unknown |
| Jan 2022 | WHEELS | Purchased 2018 truck new from dealer on 2/19. Came with 20" rims and the spare tire is on a17"rim. Currently, there is a GM recall # N212346510 and NHTSA campaign #21V985000 for this issue. My truck is not included. Hazard: Based on failure of the anti-lock braking system when operating vehicle with three 20" rims and one 17" spare my vehicle should be include in the recall. | Crash: No Fire: No | Unknown |
| Jan 2022 | UNKNOWN OR OTHER | My rear back heated window on the passenger side popped and shattered the window while I was sitting in the passenger’s seat waiting for my husband. The truck smelled like a sweet wire smell and then I heard a loud pop. I looked back and the back window panel was shattered. I do see that there were recalls on some of these windows. | Crash: No Fire: No | Unknown |
| Jan 2022 | ELECTRICAL SYSTEM,SERVICE BRAKES | Im getting a service trailer brake system soon message on dash. | Crash: No Fire: No | Unknown |
| Jan 2022 | SERVICE BRAKES | While driving parking lot speeds, when I pressed the brake pedal, it was very very difficult to push causing me to nearly rear end the car in front of me. This happened intermittently during a short time frame (5 minutes). While standing on the brake pedal hoping to stop in time, the brake pedal shook like the Antilock brakes were activating. This caused it to be even more difficult to stop in time. My vehicle is currently at my local dealership's service shop. When the issue occurred, a message stating "Service Brake Assist" popped up in my display. | Crash: No Fire: No | Unknown |
| Jan 2022 | ELECTRICAL SYSTEM | The contact owns a 2018 GMC Sierra 1500. The contact stated while driving approximately 70 MPH, the trailer wiring harness system warning message was illuminated. The vehicle was taken to a local dealer where it was diagnosed with needing the wiring harness replaced; however, the vehicle was not repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 77,000. | Crash: No Fire: No | 77,000 |
| Jan 2022 | ELECTRICAL SYSTEM,SERVICE BRAKES | At 50,000 miles the "service trailer brake system" error message appears constantly due to factory defects and its very common. These trucks should be recalled everyone is in danger on the roads and its a very common problem. I have not taken it to the dealer because i should not have to pay for this very common problem, it should be recalled. | Crash: No Fire: No | Unknown |
| Jan 2022 | SEAT BELTS | Driver's side seat belt receptacle does not hold. It is difficult to get seatbelt to latch properly. Sometimes it latches and releases later. Dealer confirmed seat belt receptacle needed to be replaced. | Crash: No Fire: No | Unknown |
| Dec 2021 | POWER TRAIN | During down shifting in lower gears while reducing speed , transmission makes a loud noise followed by vehicle hard lounging forward . Occurance is intermittent and unpredictable . In city traffic this has potential to cause an accident because vehicle lounges forward when speed is reduced . Vehicle has 18900 miles . Made in 2017 . | Crash: No Fire: No | Unknown |
| Dec 2021 | SUSPENSION,POWER TRAIN | VEHICLE VIOLENTLY SHAKES AT ALL SPEEDS. DEALER BLAMED TIRES, I HAD NEW TIRES INSTALLED, STILL SHAKING. DEALER SAYS "NO PROBLEM FOUND, OPERATING AS DESIGNED" TRUCK IS A NUISANCE TO DRIVE, SHAKING BADLY | Crash: No Fire: No | Unknown |
| Dec 2021 | LANE DEPARTURE,FORWARD COLLISION AVOIDANCE | Driver Assist-Lane Keeping Assist-Forward Collision Warning-Automatic Emergency Breaking Life Threatening When System Fails and is Intermittent . Vehicle has been said to be dangerous to drive by GM Tech/Can cause life threatening conditions. Fault has been confirmed by Dealership. WARNING LAMP> "SERVICE DRIVER ASSIST SYSTEM" Friday 3 December 2021 at approximately 21340 miles. | Crash: No Fire: No | Unknown |
| Nov 2021 | ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL,SERVICE BRAKES | The truck displayed warning lights for ABS, traction control, trailer brakes, and front park assist. Additionally speed control (cruise) did not function. This presented a safety issue. I took to dealer asap. They repaired by replacing left rear wheel speed sensor. Cost about $216. Appears to work correctly at this time. | Crash: No Fire: No | Unknown |
| Oct 2021 | POWER TRAIN | TRANSMISSION IS SLAMMING VIOLENTLY DURING SHIFTING, TRANSMISSION FLUID IS DARK AND CONTAMINATED. DEALER SAYS-" OPERATING AS DESIGNED, NO ISSUE FOUND" ALSO TRUCK SHAKES AND VIBRATES VIOLENTLY WHILE DRIVING | Crash: No Fire: No | Unknown |
| Oct 2021 | ELECTRICAL SYSTEM | BATTERY DIES AFTER 5DAYS OF NOT BEING DRIVEN. BATTERY CONTINUES TO GO DEAD, DEALER STATES NOTHING IS WRONG. NO REPAIRS WERE MADE. STRANDED 5 TIMES WITH A DEAD BATTERY | Crash: No Fire: No | Unknown |
| Oct 2021 | ENGINE | 47,012 MILES RADIATOR FAILURE, LEAKING BADLY. GM DENIED REPAIR UNDER WARRANTY | Crash: No Fire: No | Unknown |
| Aug 2021 | VEHICLE SPEED CONTROL | Vehicle suddenly went into Reduced Engine Power while driving in heavy traffic. Vehicle immediately began to slow down and although there was some throttle response it was difficult to maneuver through traffic to get to the side of the road. This event happened around the 31,000 mile mark. The Reduced Engine Power message came on, but I do not remember hearing an audible alert. Being a 40 year Automotive Technician for GM, I am familiar with pulling codes and replacing parts. I called the dealership to see if this was covered by warranty and was told no. After pulling the codes, I personally replaced the Throttle Body Sensor and the Accelerator Pedal Assembly, but the vehicle continued to go into Reduced Engine Power mode. I took the vehicle into the dealership and they diagnosed the cause as a corroded connector. The connector was replaced and the vehicle was returned to me. After a little over one month and less than 1,000 miles the vehicle is once again going into Reduced Engine Power mode. I can have my vehicle available for inspection if necessary. | Crash: No Fire: No | Unknown |