Here is the description for the high pressure fuel pump used in the Mercedes-Benz C204 / W212 with the 1.8L M271 DE18LA (CGI) engine:

Mercedes-Benz C204 / W212 1.8 CGI M271 High Pressure Fuel Pump Description

Component: High Pressure Fuel Pump (HPFP)

Engine Code: M271 DE18LA (1.8L Turbocharged Direct Injection - CGI)

Model Fitment:

• Mercedes-Benz C-Class C204 (C180, C200, C250)
• Mercedes-Benz E-Class W212 (E200, E250)
  Fuel System: Direct Injection (CGI – Charged Gasoline Injection)
  Fuel Pressure Output: ~100 to 200 bar (varies based on engine load)

Function:

• Supplies high-pressure fuel to the direct injectors from the low-pressure fuel pump.
• Mounted on the engine and driven mechanically by the camshaft.
• Essential for atomizing fuel directly into the combustion chamber for better efficiency and performance.

Common OEM Part Numbers (for reference):

• A2710700501
• A2710700401
• Bosch equivalent: 0261520140

Symptoms of a Failing High Pressure Pump:

• Engine hesitation or stalling
• Poor acceleration or limp mode
• Hard starting or no start
• Fault codes (e.g., P0087 – Fuel Rail/System Pressure Too Low)

Let me know if you need info on compatible models, removal steps, or replacement brands (e.g., Bosch, VDO).