2015 MERCEDES-BENZ C-Class M274 DE20 LA/M276 DE35 LA (W205)

Engine identity

Oils and fluids

Service and parts data

Common and chronic problems

• Timing chain tensioner wear on some M274 4-cylinder engines
• Water pump and thermostat issues on M276 engines
• Potential diesel particulate filter clogging on diesel models
• Electrical gremlins with multimode transmissions occasionally reported

First checks

• Verify service history for timing chain and water pump replacements
• Inspect oil consumption and turbo boost performance
• Scan for transmission fault codes after test drives
• Check for coolant leaks and thermostat operation

Vor dem Teiletausch

• Save fault codes and freeze-frame data before clearing anything.
• Check engine oil, coolant and transmission fluid using the correct temperature and service procedure.
• Verify power, ground, connectors, hoses, leaks and live data before replacing expensive parts.

Important notes

• Engine and transmission specs vary by specific market; North America often had fewer diesel options.
• W205 generation introduced new safety and technological features over predecessor.
• 2015 is first model year of W205 C-Class globally launched.