The 2021 Highlander is generally solid, but the 3.5L V6 has shown serious oil consumption issues leading to catastrophic engine failures, while the hybrid's 2.5L has proven far more reliable. Transmission cooling system and mount failures also appear more frequently than expected for a newer platform.
Symptoms: Low oil warning light appearing between oil changes, Burning oil smell from exhaust, Blue smoke on cold start or acceleration, Sudden knocking or loss of power if oil starvation occurs, Check engine light with misfire codes
Fix: D-4S direct injection piston ring design allows carbon buildup and ring flutter, leading to 1 qt per 1,000 miles consumption or worse. Minor cases may respond to top-end cleaning and ring soak treatments (4-6 hours labor). Severe cases require full engine rebuild with updated pistons and rings (25-35 hours), or short block replacement (20-28 hours). Toyota has extended warranty coverage on some VINs but not all qualify.
Estimated cost: $6,500-12,000
Transmission Oil Cooler Line Leaks
Common · medium severity
Typical onset: 50,000-90,000 mi
Symptoms: Red fluid pooling under vehicle near front, Transmission temperature warning on dashboard, Burnt transmission fluid smell, Slipping or delayed engagement when hot
Fix: Cooler line fittings corrode or crack where they connect to radiator assembly, particularly in salt-belt states. Requires cooler line replacement and sometimes radiator if integrated cooler is damaged. 2-3 hours labor plus fluid flush. Catch it early before transmission overheats.
Estimated cost: $450-850
Transmission Mount Failure
Occasional · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Clunking when shifting from park to drive or reverse, Vibration through cabin at idle, especially with A/C on, Excessive engine rocking visible from outside during acceleration, Transmission shifter feels sloppy
Fix: Rear transmission mount separates or hydraulic portion fails, allowing powertrain to shift excessively. Requires subframe lowering on some trims for access. 2.5-4 hours labor depending on AWD configuration. Often replace engine mounts at same time if original.
Estimated cost: $550-950
Head Gasket Leaks (3.5L V6, Early Build)
Rare · high severity
Typical onset: 70,000-110,000 mi
Symptoms: White sweet-smelling exhaust smoke, Coolant loss with no visible external leaks, Overheating under load, Milky oil on dipstick or oil cap, Coolant in overflow tank bubbling at idle
Fix: Some early 2020-2021 model year V6 engines had head gasket sealing issues, possibly related to block deck machining tolerances. Both heads typically need to be done. 18-24 hours labor includes machining if heads are warped. Must pressure test block for cracks before reassembly.
Estimated cost: $4,200-6,800
Fuel Delivery Issues / Clogged Fuel Filter
Occasional · medium severity
Typical onset: null
Symptoms: Rough idle or stalling after refueling, Loss of power under acceleration, Check engine light with fuel trim codes, Hard starting after sitting overnight, Hesitation at highway speeds
Fix: In-tank fuel pump assembly filter screens clog prematurely, possibly from contaminated fuel or tank debris. Some correlation with specific fuel brands or stations. Requires dropping tank and replacing entire pump assembly (filter not serviceable separately on this generation). 3-4 hours labor.
Estimated cost: $850-1,400
Owner tips
3.5L V6 owners: check oil level every 1,000 miles religiously — catch consumption early before engine damage occurs
Use Top Tier fuel only and keep tank above 1/4 to minimize fuel system issues
Inspect transmission cooler lines annually in rust-belt states; early replacement beats tow truck bills
Hybrid models show significantly fewer powertrain issues — strongly consider them over V6 for longevity
Buy the hybrid with confidence; approach the 3.5L V6 with caution and budget for potential engine work — verify oil consumption history before purchase.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: AGM battery required for hybrid system; located in engine compartment
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Every control module on the 2020-2026 Toyota Highlander — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
⚠️ Sensor calibration may be required; usually self-learning after installation
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2021-2024 Highlander and Highlander Hybrid vehicles. The second-row seat backs may fail to lock into position during seat back adjustment.
Consequence: A seat back that fails to lock may not properly restrain an occupant during a crash, increasing the risk of injury.
Remedy: Dealers will replace the return springs in the seat back recliner assemblies, free of charge. Interim letters notifying owners of the safety risk were mailed April 27, 2026. Additional letters will be sent once the final remedy is available, anticipated August 27, 2026. This is a phased recall. Owners may contact Toyota’s customer service at 1-800-331-4331. Toyota's numbers for this recall are 26TB06 and 26TA06.
TIRES · 24V452000
2024-06-18
Southeast Toyota Distributors, LLC (SET) is recalling certain 2021-2024 Highlander vehicles. The 20-inch accessory tires with an insufficient load rating for the vehicle's Gross Axle Weight Rating (GAWR) were installed. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 110, "Tire Selection and Rims."
Consequence: Tires with an insufficient load rating can be overloaded and fail, increasing the risk of a crash.
Remedy: SET will inspect and replace the tires and information placard, as necessary free of charge. Owner notification letters were mailed August 16, 2024. Owners may contact SET's customer service at 1-866-405-4226. SET's number for this recall is SET24A.
AIR BAGS:SENSOR:OCCUPANT CLASSIFICATION · 23V865000
2023-12-20
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2020-2021 Avalon, Avalon Hybrid, Corolla, Highlander, Highlander Hybrid, RAV4, RAV4 Hybrid, Lexus ES350, Lexus RX350, Lexus RX450H, 2021 Sienna Hybrid, Lexus ES250, 2020-2022 Camry, Camry Hybrid, and ES300H vehicles. A short circuit may develop in the Occupant Classification System (OCS) sensor, preventing the front passenger air bag from deploying.
Consequence: An air bag that does not deploy during a crash increases the risk of injury.
Remedy: Dealers will inspect and replace the sensor as necessary, free of charge. Interim letters notifying owners of the safety risk were mailed in February 2024. Some final remedy owner letters were mailed October 31, 2024. Letters will continue to be mailed in phases through January 2026. Owners may contact Toyota customer service at 1-800-331-4331. Toyota's number for this recall is 23TB15/23TA15 Lexus 23LB03/23LA03.
STRUCTURE:BODY:BUMPERS · 23V720000
2023-10-26
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2020-2023 Highlander & Highlander Hybrid vehicles. During normal vehicle operation, minor impact to the front lower bumper cover may result in the cover coming loose or detaching.
Consequence: A detached front bumper cover can become a road hazard, increasing the risk of a crash.
Remedy: Dealers will repair or replace the upper and lower front bumper covers as necessary, free of charge. Owner letters were mailed April 22, 2024. Owners may contact Toyota customer service at 1-800-331-4331. Toyota's number for this recall is 23TB12/23TA12.
Performance
Horsepower
243hp
Torque
175lb-ft
0–60 mph
7.3sec
Quarter mile
15.7sec
Top speed
112mph
Fuel economy (EPA)
City
35mpg
Highway
35mpg
Combined
35mpg
Fuel
Regular Gasoline
Capability & size
Towing capacity
3,500lb
Payload
1,380lb
Curb weight
4,510lb
EPA class
Standard Sport Utility Vehicle 4WD
Wiper blades
Fourth generation (XU70). Standard hook-type attachment for front blades.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2021 Toyota Highlander 2.5L I4 Hybrid and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.