Circuit Description
WARNING: This page is about a different car, the 1995 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
Exhaust Gas Recirculation (EGR) system recirculates exhaust gas through intake system to reduce combustion temperature and NOx emissions. The amount of EGR valve opening is regulated by the EGR vacuum modulator according to engine load. Vacuum source to valve is controlled by the Vacuum Switching Valve (VSV), which is operated by ECM.
The EGR valve is closed (VSV on) under the following conditions:
- Coolant temperature below 140°F (60°C).
- Vehicle under deceleration.
- Light engine load.
- Engine racing.
Code is set when EGR gas temperature sensor value does not exceed 72°F (40°C) above ambient air temperature after vehicle is operated for 3 to 5 minutes (50 MPH or more). Possible causes are:
- EGR valve stuck closed.
- VSV short circuit.
- EGR gas temperature sensor open circuit.
- EGR vacuum hose disconnected.
- ECM.