Exhaust Gas Recirculation: Testing and 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. With engine at operating temperature, disconnect exhaust gas recirculation vacuum line from exhaust gas recirculation valve.
2. Connect a hand held vacuum pump to exhaust gas recirculation vacuum line.
3. Apply 8 inches of vacuum, engine should idle roughly or stall and exhaust gas recirculation valve should hold vacuum.