What are the most common problems with the 2021 BMW M340i?

The 3.0L turbocharged inline-six engine provides spirited acceleration.

How many recalls does the 2021 BMW M340i have?

The 2021 BMW M340i currently has 10 recalls on file. Review the full recall report to see affected components and available remedies.

Is the 2021 BMW M340i a good buy used?

Verdict: Proceed with caution. The 3.0L turbocharged inline-six engine provides spirited acceleration. Rear-wheel drive offers engaging handling characteristics. Expect premium fuel costs and a combined 26 MPG. Ten recalls have been issued, with seat belts and electrical systems being frequent concerns. No consumer complaints were logged, but recalls indicate potential systemic issues. Always verify service history, open recalls, and maintenance records before purchasing.

What maintenance costs should I expect for the 2021 BMW M340i?

Refer to the maintenance cost guide for interval schedules, DIY difficulty ratings, and typical repair cost ranges for the 2021 BMW M340i.

2021 BMW M340i Report

Known issues, recalls, running costs, and what to check before you buy.

Updated Jun 4, 2026Daniel Wilson

Overall Score

Our Verdict

Proceed with caution

Key Takeaways

The 3.0L turbocharged inline-six engine provides spirited acceleration.
Rear-wheel drive offers engaging handling characteristics.
Expect premium fuel costs and a combined 26 MPG.
Ten recalls have been issued, with seat belts and electrical systems being frequent concerns.

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Overview

2021 BMW M340i

The 2021 BMW M340i presents a compelling blend of potent performance and luxury, making it an attractive option on the used market. Its 3.0-liter turbocharged inline-six engine delivers robust power, complemented by a responsive automatic transmission and rear-wheel drive dynamics. While the EPA estimates a combined 26 MPG, expect higher fuel costs given its premium fuel requirement. The vehicle's safety ratings are not available, but it has a notable history of 10 recalls, primarily related to seat belts and electrical systems. Despite a lack of reported consumer complaints, the number of recalls suggests potential for early-life issues.

Critical Failure Risk

Multiple recalls have targeted seat belt components, including buckle assemblies and retractors. These issues can range from warning light malfunctions to potential failures in restraint function.

Early detection can help you avoid a $300-$700 repair.

Open Maintenance Analysis →

Safety & Bulletins

Open Recalls10

Service Bulletins0

Full Recall History →

Owner Complaints

No primary complaint themes found.

Detailed Issue Breakdown →

Performance & Efficiency

Fuel Efficiency

Combined

MPG

City

MPG

Highway

MPG

Full Vehicle Specifications ↓

Reliability

Practicality

The score is dragged down by its weaker day-to-day practicality signals.

Buyer Fit

Who This Car Is For

Best for

Drivers prioritizing performance and engaging driving dynamics.

+2 more buyer-fit notes in the full report

Avoid if

Budget-conscious buyers seeking minimal ownership risk.

+2 more buyer-fit warnings in the full report

2021 BMW M340i Reliability Analysis

Specs

Vehicle Specs

Fuel Type: Premium
Seating Capacity: 5
Transmission: Automatic
Drivetrain: Rear-Wheel Drive
Body Style: Sedan
EPA Combined MPG: 26

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Most Common Issues

1. Seat Belt Assembly Issues

Most reported

Usage data observed

2. 48V Battery Connection Faults

Usage data observed

See all common issues in the maintenance guide

First Service Interval

- Oil Change (5W-30 Synthetic) (Parts: 5W-30 Synthetic Oil, Oil Filter) - Tire Rotation and Inspection - Brake System Inspection

Est. shop cost: $150 - $250

10,000 mi

Unlock the full maintenance guide for every scheduled service interval and cost forecast.

Full pre-purchase inspection checklist

Complete maintenance schedule (3 service intervals)

Repair forecasts with mileage and cost context

Full buyer-fit guidance and who should avoid it

Full specs and trim-level context

10 recall campaign details & remedy notes

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FAQ

Is the 2021 BMW M340i reliable?

The CarFocal Reliability Score for the 2021 BMW M340i is 8.4/10. Reliability score is 8.4/10. NHTSA recalls: 10. Owner complaints: 0.

How practical is the 2021 BMW M340i for daily use?

Practicality score is 4.7/10. The score is dragged down by its weaker day-to-day practicality signals. EPA combined economy is 26 MPG. Seating capacity is 5.

What is the overall score for the 2021 BMW M340i?

The CarFocal Overall Score for the 2021 BMW M340i is 6.9/10. Overall score is 6.9/10 (Good). Confidence 55%. Maintenance 8.6/10. Practicality 4.7/10.

What does it cost to own and maintain a 2021 BMW M340i?

Based on Carfocal's data, First listed service: - Oil Change (5W-30 Synthetic) (Parts: 5W-30 Synthetic Oil, Oil Filter) - Tire Rotation and Inspection - Brake System Inspection at 10,000 miles. Estimated first-year maintenance: $500 - $800. Repair prediction highlight: Seat Belt Assembly (typical at 30,000 miles, estimated cost Min: $200 • Max: $600).

What engine is in the 2021 BMW M340i?

Engine specs list 6 • 3.0.

What transmission does the 2021 BMW M340i use?

According to CarFocal's specs for the 2021 BMW M340i, transmission is Automatic. The paired drivetrain is Rear-Wheel Drive.

Does the 2021 M340i require Premium gas?

Manufacturer fuel recommendation: Premium.

What is the combined EPA MPG for the 2021 BMW M340i?

EPA combined estimate is 26 MPG.

What driver assistance and safety features are available on the 2021 BMW M340i?

12 standard and 4 optional driver assistance features. Key features include Anti-lock Braking System, Electronic Stability Control, Traction Control.

How many people fit in a 2021 BMW M340i?

According to CarFocal's specs for the 2021 BMW M340i, seating capacity is 5.

What body style is the 2021 BMW M340i?

According to CarFocal's specs for the 2021 BMW M340i, body style is sedan.

What drivetrain does the 2021 BMW M340i use?

According to CarFocal's specs for the 2021 BMW M340i, drivetrain is Rear-Wheel Drive. Transmission is Automatic.

Are there open safety recalls on the 2021 BMW M340i?

This model year has 10 official safety campaigns listed.