Exhaust Gas Recirculation: Description and Operation

Exhaust Gas Recirculation (EGR) System

WARNING: Observe the following for all installations, especially in engine compartment due to dense construction:
- Route lines of all types (e.g. for fuel, hydraulics, coolant and refrigerant, brake fluid, vacuum) and electrical wiring so that the original path is re-established.
- Watch for sufficient clearance to all moving or hot components.

Function
Activation of Exhaust Gas Recirculation (EGR)system occurs from Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248- via EGR Vacuum Regulator Solenoid Valve -N18- to EGR valve. The mechanical EGR valve with cone-shaped valve plunger makes different opening diameters possible at different valve lift. Every relevant valve position is possible via
cyclic activation.

NOTE:
- Always replace self-locking nuts.
- Components marked with * are tested via On Board Diagnostic (OBD), Diagnostic mode 3: Check DTC memory.