Exhaust gas recirculation function - GF14.20-P-3000D

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

ENGINE 104.942 in MODEL 124.008 / 028 / 029 / 088 with CODE (491) USA version with CODE (498) Japanese version

ENGINE 104.992 in MODEL 124.032 / 052 / 066 / 092 with CODE (491) USA version with CODE (498) Japanese version

ENGINE 104.991 in MODEL 129.063 up to 31.7.96 with CODE (491) USA version with CODE (498) Japanese version

ENGINE 104.994 in MODEL 140.032 / 033 up to 31.7.96 with CODE (491) USA version with CODE (498) Japanese version

ENGINE 104.941 in MODEL 202.028 with CODE (491) up to Model Year 96 USA version with CODE (498) up to Model Year 96 Japanese version

ENGINE 104.995 in MODEL 210.055 with CODE (491) up to Model Year 96 USA version with CODE (498) up to Model Year 96 Japanese version

Fig 1: Exhaust Gas Recirculation Function Diagram

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Exhaust gas is recirculated as a function of the map in the engine control unit as soon as the following criteria are met:

Coolant temperature >48°C
Engine speed <3500 rpm
Part throttle

The EGR switchover valve (Y27) is actuated at the ground end and switches vacuum to the EGR valve, as a result of which this valve is opened.

Low-oxygen exhaust is inducted dependent on the position of the throttle valve. As a result, the fuel/air mixture contains less oxygen. This results in a reduction in the combustion temperature and the formation of NO_x is reduced.

Control module (HFM-SFI) position/task/design/function		GF07.51-P-4103D
EGR valve position/task/design/function		GF14.20-P-3103G
Coolant temperature sensor position/task/design/function	(B11/3)	GF07.04-P-5026GA
EGR switchover valve position/task/design/function		GF14.20-P-3100F
Crankshaft position sensor position/task/design/function		GF07.04-P-4116G
EA/CC/ISC actuator position/task/design/function		GF30.22-P-4010F
Hot film mass air flow sensor position/task/design/function		GF07.07-P-4118G
Survey of pneumatic diagrams (HFM-SFI)		PP07.51-P-1100D
Overvoltage protection relay position/task/design/function	Model 124, 202 up to 7/96	GF54.10-P-4100A
Fuse and relay module	Model 202 as of 8/96
Base module position/task/design/function	Model 129, 140	GF54.21-P-4013L
Relay module position/task/design/function	Model 170, 210	GF54.10-P-4033K