The redesign year, and it launched loud — the most-complained-about Tahoe we cover, with 16 recalls and the engine at the center.

On a 5.3L truck, the cylinder-deactivation lifter problem carries over from the Silverado family and gets worse. DFM can deactivate any of all eight cylinders, and mechanics are blunt that its lifters fail more often and at lower mileage than the old AFM — one owner in the file lost a lifter that damaged the camshaft at about 70,700 miles. Symptoms are a tick, misfire, and power loss; the repair is lifters plus a camshaft for several thousand dollars, with no recall — only a class action and reactive warranty repairs that owners say sometimes recur. A cold-start valvetrain tick is a walk-away; a DFM disabler (~$150) or a documented lifter history is the protection.

The fifth-generation Tahoe's 10-speed automatic can shift harshly, hesitate from park, or slip, and the file has valve-body and control-valve failures — 'the valve body needs replaced… known issues in the 2021 Tahoe,' one owner was told, sometimes not covered out of warranty, with a transmission failure at 108,000 miles. GM's transmission-control-valve wear is covered by a 15-year/150,000-mile Special Coverage for 2021–2022 (from the in-service date, regardless of ownership) — a new valve body free, with reimbursement for prior repairs. Test-drive for harsh or delayed shifts and confirm the truck is inside that coverage window.

As a first-year body, 2021 drew a stack of genuine but free-to-fix recalls. The hazards worth naming: a fuel tank missing adhesive that can leak (21V064, fire risk), a fuel-pump power-control module that can stall the engine (21V739), power-steering software that can drop assist (21V455, over-the-air), a rear driveshaft not heat-treated that can fail (22V036), and several seat-belt items including a trapped second-row center latch (21V210) and misrouted third-row belts (21V190). The key on a used 2021 is confirming by VIN that every one of these was completed.

The 10.2-inch touchscreen can freeze, lag, or blank out, affecting navigation and phone mirroring; a dealer reflash runs about $150–$300, and on higher-mileage trucks the dash wiring can degrade from heat and vibration. Even Edmunds' own long-term 2021-era Z71 called the screen 'finicky.' It's an annoyance rather than a safety issue — test the system thoroughly on a pre-purchase inspection.