The Issue

The M274 engine is a very well-built, high featured engine . In traditional MB fashion, it's highly sophisticated and highly engineered, and quite difficult to work on. You also need a set of special tools to set timing properly. 

A very common failure in the W205 generation of the Mercedes-Benz C300 with the M274 4-Cylinder turbo engine is the P001685 code. The issue is caused by a manufacturing defect causing an internal pin in the camshaft sprockets to dislodge, and impact the ability of the sprocket to maintain the timing of the engine. 

Symptoms

Some of the symptoms you will experience if you have this issue are:

• Slow crank times
• Check Engine Light on permanently
• Code P001685 alone, other codes indicate other issues.

The Repair

The overpriced franchised dealer quotes an ungodly amount to replace the camshaft sprockets alone (we just saw an estimate for $7,000). We recommend doing the job right, and replace the actual chain, guides, tensioner, and oil chain. All with updated parts, for perfect first time fit and a guaranteed repair, for a fraction of the price.