Passat L4-1984cc 2.0L DOHC (1991)
Fig. 38 Vacuum Thermo-switch, 16V (California)
A thermo-Vacuum valve, is installed in the primary vacuum supply line to the vacuum amplifier. This valve will open and allow the EGR valve to
operate when the coolant temperature reaches approximately 50°C (122°F). The valve will close when the coolant temperature is below approximately
27°C (81°F).
TEMPERATURE SENSOR
Fig. 39 Egr Valve Location, 16V (California)
An EGR temperature sensor is located in the intake manifold near the EGR valve. It is used to inform the CIS-E Motronic control unit if the EGR system
is functioning properly.
The sensor is used to measure the temperature of the recirculated exhaust gas coming from the valve. This sensor is a malfunction detection sensor only.
If the EGR valve, temperature sensor or wiring fails, the fault is stored in the CIS-E Motronic's permanent fault memory, and also illuminates the
"CHECK" light which is located to the right of the instrument panel.
All emissions related faults will be stored in the CIS-E Motronic's fault memory, and on California vehicles, the engine "CHECK" light to the right of the
instrument panel will illuminate if a fault exists.
