The 2021 Hyundai Elantra has several recurring issues that prospective buyers should be aware of, based on extensive owner feedback. Electronic system malfunctions top the list, with multiple owners reporting forward collision sensor failures, infotainment screen blackouts, and erratic behavior from safety systems like lane departure warning.

Battery problems appear surprisingly common for such a new vehicle, with owners reporting battery failures at just two years of age. One owner specifically noted their battery dying after only two years of use, coinciding with forward sensor malfunctions. This early battery failure rate is concerning for a vehicle that should easily provide 4-5 years of battery life.

Engine-related issues include overheating problems in vehicles with extremely low mileage - one owner reported overheating twice in less than three months with under 1,600 kilometers on the odometer. Engine sludge formation has also been documented, with dealers claiming it's normal for winter driving conditions, though experienced owners dispute this explanation.

Build quality concerns manifest in various ways, including trunk closure problems, squeaking door panels, poor door seal fitment causing wind noise, and peeling alloy wheels. The air conditioning system also shows weaknesses, with owners reporting inadequate cooling performance in temperatures above 84°F, causing discomfort during hot weather driving.

Safety system malfunctions create both annoyance and potential hazards, with lane departure assist described as erratic enough to make drivers appear intoxicated, and emergency braking systems activating inappropriately on highways due to construction barriers or road imperfections.

Despite reliability concerns, many 2021 Hyundai Elantra owners are genuinely enthusiastic about their vehicle's strengths, particularly its exceptional fuel economy and striking design. Owners consistently report achieving 40+ MPG in real-world driving, with some achieving 41.6 MPG on highway trips. This impressive efficiency, combined with the car's modern, 'origami-like' styling, creates a compelling package that stands out in parking lots.

The interior space and comfort level surprise many owners, especially those coming from larger vehicles. Multiple reviews mention the generous cabin space for four adults, which exceeds expectations for a compact sedan. The heated seats receive particular praise for their comfort and therapeutic benefits, with one owner specifically noting their effectiveness for back comfort during long commutes.

Technology integration earns high marks from most owners, with the infotainment system, safety features, and convenience items like remote start with climate control being frequently mentioned positives. The comprehensive safety suite included even on base models provides peace of mind, and when working properly, systems like blind spot monitoring and forward collision warning are appreciated.

Value proposition remains a strong selling point, with owners appreciating the extensive feature list relative to the purchase price. The included maintenance programs, such as free oil changes for 36,000 miles or three years, add tangible value. Many owners note getting 'Limited-level' features in lower trim levels, making the vehicle feel well-equipped regardless of which variant they chose.

The 2021 Hyundai Elantra's long-term ownership costs present a mixed picture, with excellent fuel economy offset by potential repair expenses and early component failures. Owners consistently report exceptional gas mileage, with real-world averages of 40-42 MPG being common, translating to significant fuel savings over the vehicle's lifetime. At current gas prices, this efficiency can save owners $500-800 annually compared to less efficient competitors.

Maintenance costs start favorably thanks to Hyundai's included service programs. Many owners benefit from free oil changes for 36,000 miles or three years, though some express concern about the recommended 7,500-mile oil change intervals being too long for optimal engine health. The CVT transmission, while smooth in operation, raises long-term cost concerns among owners who worry about premature failure and expensive repairs outside of warranty coverage.

Repair costs can be substantial when problems occur, particularly for electronic system failures and transmission issues. While warranty coverage addresses major component failures like the transmission replacement at 7,000 miles, owners face significant inconvenience and potential rental car costs during extended repair periods. Some owners report 40+ day waits for transmission replacements due to parts availability.

Insurance costs generally remain reasonable for the Elantra due to its strong safety ratings and relatively modest performance specifications. However, early quality issues may impact long-term reliability ratings, potentially affecting both insurance premiums and resale values as the vehicle ages beyond its comprehensive warranty period.

While the 2021 Hyundai Elantra's modification scene is still developing given the model's relative newness, owner feedback reveals several common upgrade areas and practical modifications. Lighting improvements top many owners' wish lists, particularly for SE, SEL, and N-Line trims that use halogen projector headlights rather than the LED units found on Limited models. Many owners express frustration with the inadequate nighttime illumination and seek aftermarket LED or HID upgrades, though finding compatible replacements has proven challenging.

Protective modifications are gaining popularity among practical owners. One innovative owner in Oklahoma created a custom condenser guard using rabbit wire to protect the AC condenser from large insects, demonstrating the kind of practical problem-solving that often leads to popular modifications. Paint protection film and ceramic coatings are increasingly common given owners' complaints about body panels being susceptible to damage from minor impacts.

Performance modifications remain limited for the naturally aspirated 2.0L engine, though the N-Line's turbocharged 1.6L offers more potential. Most owners focus on aesthetic improvements like window tinting, wheel upgrades, and interior accessories rather than engine modifications. The CVT transmission also limits performance modification potential compared to traditional automatic or manual transmissions.

Comfort and convenience upgrades are popular, with many owners adding aftermarket accessories to address specific complaints like sun visors that don't stay in place or adding additional storage solutions. The relatively new platform means aftermarket support is still developing, but owner ingenuity continues to drive custom solutions for common issues.

The 2021 Hyundai Elantra consistently exceeds EPA fuel economy estimates in real-world driving, with owners regularly reporting 40+ MPG in mixed driving conditions. Multiple owners document achieving 40-42 MPG averages, with one owner specifically noting 34 MPG in city driving and 41.6 MPG on highway trips. This performance often exceeds the EPA's combined estimate, making the Elantra one of the most fuel-efficient non-hybrid sedans available.

Driving conditions significantly impact fuel economy, with owners noting the CVT transmission's efficiency in steady-state highway driving. The transmission's ability to maintain optimal engine RPM helps maximize fuel efficiency, though some owners dislike the CVT's behavior during acceleration. Cold weather operation doesn't seem to dramatically impact efficiency, with owners maintaining good fuel economy even during winter driving conditions.

Owners have discovered that the Elantra's efficiency makes it particularly suitable for long commutes and high-mileage driving. One owner accumulated 12,000 miles in just six months while maintaining excellent fuel economy, demonstrating the vehicle's capability for high-mileage use. The generous fuel tank capacity combined with the impressive efficiency provides excellent driving range between fill-ups, reducing the frequency of gas station visits.

When shopping for a 2021 Hyundai Elantra, owners strongly recommend focusing on the electronic systems during test drives and pre-purchase inspections. Test all safety features including forward collision warning, lane departure assist, and blind spot monitoring to ensure proper operation. Pay particular attention to the infotainment system's responsiveness and check that all electronic functions work consistently, as these have been problematic areas for many owners.

Trim level selection requires careful consideration of feature priorities versus potential reliability differences. The Limited trim's LED headlights offer significantly better nighttime visibility compared to the halogen projectors on SE, SEL, and N-Line models, though some owners have experienced more electronic issues with higher trim levels. The SEL trim appears to offer the best balance of features and value, providing most desired amenities without the complexity that may contribute to reliability issues.

Potential buyers should verify dealer service capabilities and reputation before purchasing, as service experiences vary dramatically by location. Some regions report six-month wait times for diagnostic work, which could be problematic if issues arise. Consider purchasing from dealers with strong service reputations and adequate technician staffing for warranty repairs.

Given the documented early reliability issues, ensuring comprehensive warranty coverage is crucial. Verify that all electronic systems, transmission, and engine components are covered under Hyundai's warranty terms. Consider extended warranty options given the potential for expensive electronic system repairs and the documented transmission failures in early production vehicles.

Owners who cross-shopped the 2021 Hyundai Elantra frequently mention comparing it against the Kia Forte, Honda Civic, and Nissan Sentra. The Elantra's standout advantage appears to be its fuel economy combined with generous interior space, often exceeding competitors in both areas. However, owners note that rivals like the Honda Civic offer better build quality and more reliable electronics, though at a higher price point.

Compared to previous-generation Elantras, current owners have mixed feelings about the redesign. One owner who traded a 2013 Elantra with over 400,000 miles noted that while the 2021 model is 'sexy as hell,' they preferred their older car's seating comfort, ground clearance, and traditional automatic transmission. This suggests that Hyundai may have prioritized style and efficiency over some practical considerations.

Against competitors like the Mazda3, owners appreciate the Elantra's value proposition and included features, though some acknowledge the Mazda's superior interior materials and build quality. The Elantra's comprehensive safety suite and generous warranty coverage help offset concerns about initial quality, providing advantages that budget-conscious buyers particularly value in the compact sedan segment.