Mercedes-Benz · Known Issues
2014 Mercedes-Benz M-Class Problems: 6 Known Issues
2014 model year · 2,880+ owner reports · Updated September 2026
2014 · All trims · All engines
Choose the year and equipment for your written issues and visual request.
2014 model year · 2,880+ owner reports · Updated September 2026
2014 · All trims · All engines
Choose the year and equipment for your written issues and visual request.
Interest applies to the selected vehicle and configuration; it is not a reservation. Voting stores a first-party identifier for up to 180 days to prevent repeat votes. No account or email is needed. Clearing cookies or using another device may count separately. Privacy
Visual coming soon
Your interest helps us choose what to build next.
Visual Known Issues · Coming soon
$4.99/month plus taxes at launch · No payment today
According to Au7o's analysis of 2,880+ owner reports, the 2014 Mercedes-Benz M-Class has 6 documented known issues, with 2 rated critical. The most serious are AIRMATIC Air Suspension Strut and Compressor Failure ($1,000-$3,500 repair) and 722.9 7G-Tronic Conductor Plate (TCM) Failure and Limp Mode ($300-$1,200 repair). The most commonly reported issue is AIRMATIC Air Suspension Strut and Compressor Failure with 2,100 owner reports. Across all issues with published estimates, repair costs range from $150 to $3,500. DIY maintenance guides at au7o.io.
Don't see your problem? Describe your symptoms to get a diagnosis, or get a full repair guide.
According to Au7o's analysis of 2,880+ owner reports, the 2014 Mercedes-Benz M-Class has 6 documented issues. The most frequently reported are: AIRMATIC Air Suspension Strut and Compressor Failure, 722.9 7G-Tronic Conductor Plate (TCM) Failure and Limp Mode, Transfer Case Chain Wear and Whining Noise. Of these, 2 are rated critical and should be addressed promptly.
The 2014 Mercedes-Benz M-Class has 6 known issues documented across 2,880+ owner reports. 2 issues are rated critical: AIRMATIC Air Suspension Strut and Compressor Failure and 722.9 7G-Tronic Conductor Plate (TCM) Failure and Limp Mode. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
Repair costs for known Mercedes-Benz M-Class issues range from $150 to $3,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, AIRMATIC Air Suspension Strut and Compressor Failure, typically costs $1,000-$3,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
The AIRMATIC air suspension on the M-Class is prone to air spring leaks and compressor failures, identical to issues on other Mercedes SUVs. The rubber air spring bladders crack from age and road debris, causing the vehicle to sag and the compressor to overwork. The M-Class weigh… Repairs typically run $1,000-$3,500. Severity: high.
The 722.9 7G-Tronic automatic transmission fitted to ML350, ML500/550 and other gasoline M-Class models uses an internal conductor plate that doubles as the transmission control module and houses the input/turbine speed sensors. Heat, ATF breakdown and vibration cause the molded-… Repairs typically run $300-$1,200. Severity: high.
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.
The 4MATIC transfer case chain in the M-Class stretches over time, producing a noticeable whining noise that increases with speed. The chain drives the torque split between front and rear axles, and excessive stretch causes imprecise torque distribution and eventually transfer ca… Repairs typically run $500-$3,000. Severity: medium.
The M276 3.5L V6 used in the W166 ML350 develops a brief but distinct rattle on cold start-up. After the car sits, oil drains from the front timing covers to the sump, leaving the secondary chain tensioners momentarily without pressure on startup. The result is chain/adjuster rat… Repairs typically run $400-$2,500. Severity: medium.
The W164 and W166 M-Class front suspension uses multiple control arms with press-fit rubber bushings and integrated ball joints (the W166 lower arm has three bushings; the upper arm has two bushings plus a ball joint). The rubber bushings dry out, crack and wear, and the ball joi… Repairs typically run $300-$1,500. Severity: medium.
The OM642 3.0L V6 diesel in the ML320/350 CDI and BlueTEC uses intake manifold swirl flaps actuated by plastic linkage rods ('swirl rods') and an electric swirl motor. Constant under-hood heat cycling makes the plastic linkage brittle, while carbon and oil from the crankcase brea… Repairs typically run $150-$700. Severity: medium.