Exhaust Gas Recirculation: Description and Operation

Exhaust Gas Recirculation System

CAUTION!
Observe the following for all installations, especially in engine compartment due to lack of room:

• Route lines of all types (e.g. for fuel, hydraulic, coolant and refrigerant, brake fluid, vacuum) and electrical wiring so that the original path is followed.

• Watch for sufficient clearance to all moving or hot components.

Function

Activation of Exhaust Gas Recirculation (EGR) system is performed by Engine Control Module (ECM) (J623) and Engine Control Module 2 (J624) via EGR Vacuum Regulator Solenoid Valve (N18) and Valve 2 for EGR (N213) to mechanical EGR valves.

The mechanical EGR valve with cone-shaped valve plunger makes different opening diameters possible at different valve lifts. Every relevant valve position is possible via cyclic activation.

• Always replace self-locking nuts.

• Components depicted here correspond to cylinder bank 2. They are different only as a mirror image of components for cylinder bank 1.

• Engine Control Modules (ECM) are equipped with On-Board Diagnostics (OBD).

• Components marked with * are tested via On Board Diagnostic (OBD) --> [ Diagnostic Mode 03 - Read DTC Memory ] Reading Diagnostic Trouble Codes

Vacuum Hoses, Connection Diagram

• Cylinder bank 1 is located in direction of travel, right.

• Cylinder bank 2 is located in direction of travel, left.





1 EGR Vacuum Regulator Solenoid Valve (N18)*

• for cylinder bank 1

• checking --> [ Exhaust Gas Recirculation Vacuum Regulator Solenoid Valve, Checking ] Exhaust Gas Recirculation Vacuum Regulator Solenoid Valve, Checking

2 EGR Vacuum Regulator Solenoid Valve

• for cylinder bank 1

• Checking mechanically --> [ Exhaust Gas Recirculation Valve, Checking ] Exhaust Gas Recirculation Valve, Checking

3 EGR Vacuum Regulator Solenoid Valve

• for cylinder bank 2

• Checking mechanically --> [ Exhaust Gas Recirculation Valve, Checking ] Exhaust Gas Recirculation Valve, Checking

4 Valve 2 for EGR (N213)*

• for cylinder bank 2

• checking --> [ Exhaust Gas Recirculation Vacuum Regulator Solenoid Valve, Checking ] Exhaust Gas Recirculation Vacuum Regulator Solenoid Valve, Checking

5 Filter

6 Vacuum connection

• Between tandem pump and brake booster

7 Tandem pump

• For fuel- and vacuum supply