EGR System Inspection

The engine control module contains memories for the ideal exhaust gas recirculation valve lift for various engine operating conditions. The valve lift sensor detects the amount of exhaust gas recirculation valve lift and relays this information to the engine control module. The engine control module then compresses this information with the ideal determined by signals from various sensors. If a significant difference exist between the two, the engine control module stops current to the solenoid valve, there by reducing vacuum applied to the exhaust gas recirculation valve.

If the exhaust gas recirculation system malfunctions, a failure code will be set in the engine control module memory and the warning lamp on the instrument panel will be illuminated.

PROCEDURE
1. Connect a suitable scan tool to the data link connector located at the lower left hand side of the instrument panel.
2. Start engine and allow to reach operating temperature.
3. Using the scan tool, command exhaust gas recirculation 50 percent On.
4. The engine should idle roughly or stall.