EngineHigh
ML250 and ML350 diesel AdBlue and NOx sensor faults
- Typically appears
- 60,000+ miles
- What to inspect
- Check for AdBlue warnings and a restart countdown
2011–2015 Mercedes-Benz M-Class · common problems & known faults
A large, comfortable SUV, sold as the ML before being renamed GLE, where diesel emissions parts and air suspension lead the checks.
Compiled & reviewed by the VehicleFaults Research Team · last reviewed October 2026
Quick answer
The most commonly reported faults on the 2011–2015 Mercedes-Benz M-Class are ML250 and ML350 diesel AdBlue and NOx sensor faults, Airmatic air suspension leaks on cars fitted with it and Oil leaks from the oil cooler and cam covers. 2 of the documented issues are rated high severity · inspect these first. Full inspection points, onset mileage and what to check are listed below.
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Build the inspection planReliability snapshot
Based on the documented faults on this page for the Mercedes-Benz M-Class.
6.3/ 10
- Critical
- 0
- High
- 2
- Medium
- 2
- Low
- 2
Guidance only · reflects reported patterns, not a specific car's condition.
Known faults to check
SuspensionHigh
Airmatic air suspension leaks on cars fitted with it
- Typically appears
- 70,000+ miles
- What to inspect
- Check the car stays level after standing
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Build the inspection planEngineMedium
Oil leaks from the oil cooler and cam covers
- Typically appears
- 80,000+ miles
- What to inspect
- Look under the engine for fresh oil
TransmissionMedium
7G-Tronic gearbox harsh shifts and conductor plate faults
- Typically appears
- 80,000+ miles
- What to inspect
- Feel for clunks and check for gearbox warning lights
ElectricalLow
Infotainment and keyless entry faults
- Typically appears
- Age-related
- What to inspect
- Test every screen and door handle
BrakesLow
Front discs and pads wearing quickly due to weight
- Typically appears
- 30,000+ miles
- What to inspect
- Check disc lips and pad depth
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Build my inspection planFrequently asked questions
Is the ML the same as the GLE?
Yes, the W166 ML was renamed GLE in 2015.
Which engine is best?
The ML250 diesel is economical; the ML350 is smoother but costs more to fix.
Is air suspension a risk?
Repairs are expensive, so check it carefully or choose a car on steel springs.
Is it good for towing?
Yes, it is a strong tow car.
Sources & further reading
Faults are compiled from documented recalls, technical bulletins, owner reports and mechanic sources, then reviewed for accuracy. This is guidance only · not a substitute for a professional inspection.
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