EGR system, overview
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1999 Volkswagen Jetta, 1998 Volkswagen Jetta, 1997 Volkswagen Passat, 1997 Volkswagen Jetta, and 1996 Volkswagen Passat. However, it is still accessible from the selected car via links, so may be relevant.
Exhaust gas is removed from the exhaust manifold -1- and enters the intake manifold -3- via the EGR vacuum regulator solenoid valve -2-.
Actuation is by vacuum from vacuum pump -4- while control is provided by the automatic glow time control module -J179- (item -8-) via the two-way valve for EGR -N161- (item -5-).
When engine is cold, under full load, certain RPM ranges and at altitudes above 3300 feet, the EGR is switched off as follows:
- At temperatures below +50 °C (122 °F) and engine is cold, EGR is switched off via sensor for engine temperature -G27- (item -6-).
- The EGR part throttle switch - F166- (item -7-) for EGR (on injection pump) ensures that exhaust gas is only recirculated during part throttle operation.
- Engine speed limiting is affected by automatic glow time control module -J179- (item -8-) and Generator terminal "W" (item -9-). When engine speed exceeds 1200 RPM, EGR is interrupted for 2 seconds. When engine speed exceeds 3200 RPM, EGR is switched off.
- At altitudes over approx. 3300 feet, EGR is switched off by altitude correction features in automatic glow time control module -8-.