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MINI · Known Issues

2021 MINI Cooper S Problems: 1 Known Issue

2021 model year · 3,500+ owner reports · Updated September 2026

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Issue summary

According to Au7o's analysis of 3,500+ owner reports, the 2021 MINI Cooper S has 1 documented issue. None of the listed issues is rated critical; this is not a complete reliability assessment. The most commonly reported issue is Direct Injection Carbon Buildup on Intake Valves with 3,500 owner reports. Across all issues with published estimates, repair costs range from $400 to $800. DIY maintenance guides at au7o.io.

In This Article

  • Cooper S Engine1
  • Recalls5
  • FAQ
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In This Article

  • Engine1
  • Recalls5
  • FAQ

All 1 Known Issue

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Community reported
3,500 owners

On the 2007-2025 MINI Cooper S, all turbocharged direct-injection MINI engines (N14, N18, B46/B48) accumulate carbon deposits on intake valves since fuel is injected directly into the cylinder rather than washing over the valves. This reduces airflow and causes rough running.

This issue also affects: BMW 2 Series, BMW 3 Series, BMW 5 Series

Common Symptoms

  • Rough idle
  • Hesitation on acceleration
  • Reduced fuel economy
  • Misfire codes
  • Loss of power

How to Fix

Walnut blast the intake valves to remove carbon deposits. This should be done every 40-60k miles as preventive maintenance. Install an oil catch can to reduce oil vapor reaching the intake.

Typical repair cost:$400 - $800

Research This Issue

Based on 3,500 owner reports

GoogleRedditYouTubeNHTSA
Community Reported
High Confidence3,500 owner reportsLast reported by owners Feb 2026Reviewed Feb 2026
NHTSA Recalls5 recalls

ELECTRONIC STABILITY CONTROL (ESC)

BMW of North America, LLC. (BMW) is recalling certain 2023-2025 BMW, MINI, and Rolls-Royce vehicles. Please see the recall report for a complete list of models and model years. The integrated brake (IB) system may malfunction and result in a loss of power brake assist or cause the Antilock Brake (ABS) and Dynamic Stability Control (DSC) systems to not function properly.

Campaign #24V10400012/02/2024

ELECTRONIC STABILITY CONTROL (ESC):CONTROL MODULE

BMW of North America (BMW) is recalling certain 2023-2024 X1, 2024-2025 X5, 2025 X6, 2023-2025 X7, 740i, 760i, 2024 XM, 530i, 540i, i7, 750e, X2, 2024-2025 i5, 2024 Rolls Royce Spectre, 2025 MINI Countryman S ALL4, JCW Countryman ALL4, and 2025 MINI Hardtop 2 Door (Cooper, Cooper S) vehicles. Please refer to the recall report for the complete list of models. The welds in the servomotor of the integrated brake control module may break, causing a loss of power brake assist and rear brake function. In addition, the Antilock Brake System (ABS) and Dynamic Stability Control (DSC) system may not function.

Campaign #24V69700018/09/2024

SERVICE BRAKES, HYDRAULIC:POWER ASSIST:ELECTRIC:CONTROL MODULE

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Other MINI Models

MINI GP17MINI Hardtop 4 Door13MINI Countryman12MINI Clubman12MINI Cooper8MINI Paceman5

Frequently Asked Questions

What are the most common MINI Cooper S problems?

According to Au7o's analysis of 3,500+ owner reports, the 2021 MINI Cooper S has 1 documented issue. The documented issue is: Direct Injection Carbon Buildup on Intake Valves. None are rated critical, but regular maintenance is recommended.

Is the MINI Cooper S reliable?

The 2021 MINI Cooper S has 1 known issue documented across 3,500+ owner reports. None of the matching records is rated critical; this is not a complete reliability assessment. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common MINI Cooper S problems?

Repair costs for known MINI Cooper S issues range from $400 to $800, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2007-2025 MINI Cooper S Direct Injection Carbon Buildup on Intake Valves?

All turbocharged direct-injection MINI engines (N14, N18, B46/B48) accumulate carbon deposits on intake valves since fuel is injected directly into the cylinder rather than washing over the valves. This reduces airflow and causes rough running. Repairs typically run $400-$800. Severity: medium.

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data sourced from 3,500+ owner reports, NHTSA recalls, TSBs, and automotive forums.

BMW of North America, LLC (BMW) is recalling certain 2025 Mini Cooper S, Mini Countryman S All4, X2, 2024 Rolls-Royce Spectre, 2023-2025 i7, 7 Series, X7, 2024-2025 i5, 5 Series, 2023-2024 XM, X1, 2024-2025 X6, and X5 vehicles. The integrated brake (IB) system may malfunction and result in a loss of power brake assist or cause the Antilock Brake (ABS) and Dynamic Stability Control (DSC) systems to not function properly.

Campaign #26V42200001/07/2026

SEAT BELTS

BMW of North America, LLC (BMW) is recalling certain 2021 2 Series (230i, 230i xDrive, M240i, M240i xDrive), 330e, 330e Xdrive, 4 Series Coupe (430i, 430i xDrive, M440i xDrive) M4 Coupe, M4 Competition Coupe, BMW 4 Series Convertible (430i, M440i), BMW X1 sDrive28i, xDrive28i, 2 Series Gran Coupe (228i, 228i xDrive, M235i xDrive), M2 Competition Coupe, 330i, 330i xDrive, M340i, M340i xDrive, M3, M3 Competition, 530i, 530i xDrive, 540i, 540i xDrive, MINI Hardtop 2 Door (Cooper, CooperS, JCW), X2 sDrive28i, X2 xDrive28i, X2 M35i, Z4 sDrive30i, Z4 M40i, MINI Hardtop 2 Door (Cooper SE), MINI Convertible (Cooper, Cooper S, JCW), MINI Clubman (Cooper S, Cooper S All4, JCW), MINI Countryman (Cooper, Cooper All4, Cooper S, Cooper S All4, JCW All4), Rolls Royce Ghost, MINI Countryman (Cooper S E All4), Rolls Royce Phantom, Rolls Royce Cullinan, and Toyota Supra vehicles. The passenger seat belt Automatic Locking Retractor (ALR) may deactivate early, before the webbing fully retracts. As such, these assemblies fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 208, "Occupant Crash Protection."

Campaign #21V55400021/07/2021

AIR BAGS: AIR BAG/RESTRAINT CONTROL MODULE

BMW of North America, LLC (BMW) is recalling certain 2020 X1 xDrive28i, X1 sDrive28i, X2 xDrive28i and X2 sDrive28i, 2020 MINI Clubman Cooper S All4, 2021 MINI Hardtop 2 Door (Cooper, Cooper S, John Cooper Works and Cooper S E) and MINI Hardtop 4 Door (Cooper and Cooper S) vehicles. Due to a problem with the rollover sensor within the air bag control unit, in the event of a rollover crash, the head air bag, seat belt pretensioners and other safety systems, may not activate.

Campaign #20V28300020/05/2020

Enter your VIN at NHTSA.gov to check recalls specific to your vehicle.