2021 Gmc Sierra 1500 — Known Issues & Recalls

Your engine is shutting off completely when you stop at red lights or stop signs, leaving you stranded in traffic and unable to move when the light turns green. This creates a serious safety risk of being rear-ended by other vehicles. Even after having your engine replaced, the problem persists and appears to be related to your truck's automatic stop-start system. The fix will likely involve diagnosing and repairing or reprogramming the auto stop-start system components.

Your 6.2L engine developed severe knocking and lost oil pressure shortly after the dealer performed a recall diagnostic and oil service. You're concerned that the recall fix may not be effective, especially since you were stranded and unable to pick up your child from daycare, and you've heard reports of replacement engines failing as well. The dealer is requiring you to tow the truck at potentially your own expense to determine if it qualifies for recall coverage. Resolving this will likely require the dealer to diagnose the engine condition and potentially replace or rebuild the engine block and related components.

Your engine has failed twice in roughly 6,000 miles of driving. The dealer confirmed that a valve dropped and damaged the cylinder wall, causing the engine to lock up without any warning lights. Your truck is currently at the GMC dealer waiting for a third replacement engine.

Your truck is experiencing severe engine problems including shuddering, rough running, and loss of power while driving at highway speeds. The check engine light came on along with a low oil pressure warning, and the engine won't restart after stalling. Even after replacing the torque converter under warranty, the issues continued and have now progressed to complete engine failure. Your engine will likely need to be replaced, which may involve diagnosing the underlying cause (possibly related to oil pressure or ignition timing based on the P0016 code) before a full engine swap is performed.

Your 2021 GMC Sierra 1500 with a 6.2L V8 engine experienced sudden engine failure without warning while driving under normal conditions. The engine threw a connecting rod and became completely inoperable, with no prior warning signs like knocking, overheating, or check engine light despite proper maintenance with manufacturer-recommended oil. This sudden loss of power created a serious safety risk while driving, especially at highway speeds. The repair will likely require complete engine replacement or rebuild.

Your engine has experienced repeated lifter failures at 5,000 miles, 86,000 miles, and 126,000 miles, each time causing a loss of power and requiring engine replacement. While some replacements were covered under warranty, you had to pay out-of-pocket for at least one engine. The replacement engines have limited remaining warranty coverage, so future repairs may be your responsibility.

You took your truck to the dealer because of an unusual engine sound, but they found nothing wrong. Four days later, a rod bearing failed while you were driving, leaving your truck unable to run. The dealer may need to inspect and potentially replace the rod bearing and perform a full engine assessment.

Your engine is losing power and making a knocking sound while driving. Multiple warning lights appeared at once: check engine (flashing), check brake system, check SRS (airbag system), and check parking brake. A mechanic diagnosed that cylinder 6 in your engine has failed and is no longer firing. The fix will likely involve replacing or rebuilding the engine, or potentially just addressing the specific cylinder through head work or valve train repair.

Your truck is showing a P1098 error code related to a coolant control valve failure. There's a service bulletin (N252508341) that addresses this issue, but your VIN apparently isn't included in the recall coverage even though your truck has the same engine and part as vehicles that are covered.

When Android Auto fails to connect to your truck's infotainment system, the entire system becomes unresponsive and unavailable, which creates a dangerous distraction while driving. You should still be able to use basic infotainment functions even when Android Auto isn't connected. The dealer and software team have conflicting explanations about who is responsible for fixing this issue. A resolution would likely require either a software update from GMC or a dealer diagnostic to identify whether the connection failure is a software or hardware problem.

Your transmission's torque converter may be failing. When you drive at speeds between 38–51 mph and maintain a steady speed, you experience a vibration that feels like driving over a rumble strip. The vibration stops if you accelerate, decelerate, or release the gas pedal. Other owners report the same issue, though no recall has been issued yet.

Your truck jerks violently when accelerating lightly and shifting gears, and you've experienced the rear wheels locking up while driving. You've visited the dealership multiple times about this issue. This likely involves transmission shift quality and brake system concerns that need professional diagnosis and repair.

Your 2021 GMC Sierra 1500 experienced engine hesitation or misfiring while driving uphill at 50-65 MPH, and the auto start/stop system failed to restart the engine after stopping. After continued driving, your truck entered limp mode with multiple warning lights illuminated. The dealer suggested this may be related to a corroded ground strap but indicated your vehicle wasn't covered under the recall due to warranty issues. Fixing this will likely involve cleaning or replacing the engine ground strap connections and a full electrical system diagnostic.

After your engine recall was repaired in 2025, your truck started experiencing intermittent electrical problems — dashboard warning lights (like service 4WD and traction control) turn on and off while driving. If you turn off the truck while these lights are on, it won't start again for about 24 hours. You're also experiencing random no-start issues that resolve after a few days, and you've noticed a scraping or squealing sound when backing up. The dealership that performed the recall repair hasn't been able to identify the root cause because these problems occur intermittently. A complete diagnosis will likely involve checking the electrical system connections and battery, testing the starter motor, and inspecting the driveline components.

Your steering may lock up or become unresponsive, making it difficult to control the vehicle's direction. You might experience erratic steering behavior that comes and goes. This issue could affect your ability to safely maneuver the truck and may require inspection of the steering system components.

While driving on the interstate at normal speeds in warm weather, your truck developed a vibration that worsened over several miles. Despite checking tire pressure and finding no visible problems, your driver's side tire suddenly blew out at 45 mph, forcing you to make a quick maneuver to avoid an accident and damaging your truck bed. The tire tread and inner fender parts were scattered into traffic, creating a hazard for other vehicles. The tire appeared to fail prematurely despite proper maintenance and inflation, and a tire replacement or inspection by a tire professional may be needed to determine the cause of the failure.

Your truck's DEF (diesel exhaust fluid) tank has failed for the second time in 14 months, and the replacement part is on nationwide backorder. Your truck has been out of service for over 2 months with no clear timeline for repair, and GM has not provided assistance despite your direct contact. The fix will require replacing the DEF tank with an OEM part once it becomes available.

Your truck is consuming oil at an unusually high rate—it lost 2 quarts in the first 2,910 miles, and continues to lose approximately 1 quart every 1,000–1,700 miles even after dealer visits. Your coolant level is also running low. The dealer has refused to investigate the root cause of the oil consumption despite your truck being under warranty, leaving you without answers or covered repairs.

Your engine shut off while driving and wouldn't restart, requiring a complete engine replacement at the dealer. After the new engine was installed with only 3,000 miles on it, you're experiencing engine noise, hard transmission stuttering, and air conditioning failure—plus the new starter had to be replaced due to a defect. The dealer took over a month to complete the initial engine replacement work.

Your 2021 GMC Sierra 1500 is making abnormal sounds while idling and using more fuel than normal, even after the dealer performed an engine test and changed your oil to a higher viscosity. You refused to bring the vehicle back for a follow-up engine test, so the underlying issue remains unrepaired. The fix will likely involve additional engine diagnostics and possibly replacing engine components like gaskets, valve covers, or the PCV system to address the noise and fuel consumption problem.