Thirty-four complaints against 865. The 4Runner's homework is a wheel balance; the Wrangler's is a park-outside fire recall.

The generation's signature complaint dominates the 2021 file: a steering-wheel shimmy around 55–65 mph, often on trucks with only a few thousand miles, that owners chase through repeated road-force balancing and alignments while dealers call it normal. Toyota's tech tips tie much of it to the factory tires, and mechanics say a body-on-frame truck on aggressive all-terrain tires is inherently prone to it — improved most by better tires and a proper road-force balance. It's a test-drive item, not a broken part or a safety defect. Drive at highway speed before buying.

Sources: NHTSA complaint database, 2021 4Runner · NHTSA recalls and manufacturer communications (shimmy/tire tech tips) · Independent mechanic/owner channel transcripts (5th-gen 4Runner, incl. Car Care Nut)

A recurring 4Runner annoyance shows up on 2021 cars: door-lock actuators failing one after another — front doors and the liftgate — at roughly a $200 part each, out of warranty once the bumper-to-bumper expires. Owners cite a class-action over the pattern. It's not a safety defect, but it's a nagging, repeating bill. Operate every lock from the fob and the switch before buying.

Sources: NHTSA complaint database, 2021 4Runner · Independent mechanic/owner channel transcripts (5th-gen 4Runner, incl. Car Care Nut)

Two generation-wide items in the 2021 file. The sunroof can shatter spontaneously ('sounded like a gunshot,' glass blowing outward) with no recall — comprehensive insurance is the backstop. And the brakes feel soft and nose-dive by design, with real but low-frequency reports of the pedal sinking or briefly losing braking; test braking from 30 mph and watch the pedal hold at a stop. TRD Pro trucks add a cold-weather Fox-shock clunk covered by a Toyota bulletin.

Sources: NHTSA complaint database, 2021 4Runner · Independent mechanic/owner channel transcripts (5th-gen 4Runner, incl. Car Care Nut)

The 4xe plug-in hybrid's defining risk. The high-voltage battery can fail internally and lead to a vehicle fire while parked or driving, so Chrysler advises owners to park outside and away from structures and not to charge the vehicle until it's repaired (23V-787, code 89A — later expanded by 24V-720 and superseded by 25V-741, code 68C). The remedy updates the battery software and replaces the battery pack as needed, free. On any 4xe, this is the recall to see fully closed in its newest form; an open one means you literally shouldn't garage the truck.

Sources: NHTSA complaint database, 2021 Jeep Wrangler and Wrangler 4xe · NHTSA recalls and manufacturer communications (4xe battery/engine recalls; Z27, XC2, Y28 programs; XF1 steering-damper warranty extension) · Independent mechanic and owner channel transcripts (JL Wrangler; 4xe reliability; death-wobble diagnosis)

Beyond the fire recall, the 4xe has a recall for a loss of communication that can shut the engine down, causing a loss of drive power (22V-865, code ZB7); the fix reprograms the hybrid control modules so a fault limps home instead of shutting off. There's also a PHEV Battery Replacement Customer Support Program (a quiet extended-coverage program, Chrysler code Z27) and a later PHEV engine-replacement warranty extension (program XC2) for misfire faults. A mechanic sums up the hybrid hardware as 'a complete train wreck' and recommends an extended warranty. Treat a 4xe as a warranty-covered-or-walk-away buy.

Sources: NHTSA complaint database, 2021 Jeep Wrangler and Wrangler 4xe · NHTSA recalls and manufacturer communications (4xe battery/engine recalls; Z27, XC2, Y28 programs; XF1 steering-damper warranty extension) · Independent mechanic and owner channel transcripts (JL Wrangler; 4xe reliability; death-wobble diagnosis)

On the standard Wrangler, the solid-axle death wobble is still the top complaint theme. A mechanic names worn ball joints as the most common cause, worse with oversized or unbalanced tires and lifts, and any slop in the track bar or steering links. There is no safety recall for the wobble itself — the steering-damper programs (XF1 warranty extension, V41 notification) covered the earlier years and, per the mechanic, are 'a band-aid.' Test for it on a rough road and a highway ramp; any shimmy is a front-end inspection.

Sources: NHTSA complaint database, 2021 Jeep Wrangler and Wrangler 4xe · Independent mechanic and owner channel transcripts (JL Wrangler; 4xe reliability; death-wobble diagnosis)