LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Audi >> 1980 >> 5000 Base, Standard Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Exhaust Gas RECIRCULATION >> Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Exhaust Gas RECIRCULATION: Description

The exhaust gas recirculation (EGR) system is used to reduce NOx emissions by recycling metered amounts of exhaust gas back into the intake/combustion system. This is done through a vacuum-controlled EGR valve which responds to a vacuum signal from the throttle housing. This signal is determined by the position of the throttle plate.

System consists of an EGR valve, temperature control valve, vacuum amplifier, vacuum delay valve (auto, trans, only) and a vacuum reservoir.

Fig 1: Exhaust Gas Recirculation (EGR) System Schematic
G09310632Courtesy of AUDI OF AMERICA, LLC