1987 Mercedes Benz 300DFACTORY OEM SERVICE PROCEDURE

EGR System: Description

These engines use a vacuum operated and electronically controlled EGR system. The system consists of a Electronic Control Unit (ECU), vacuum control valve, switchover valves, microswitches, coolant temperature switch, vacuum control flap, throttle valve housing, and a TDC transmitter. The control unit on the diesel engines is called the Electronic Diesel System (EDS) control unit.

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.