Chart C-7 Exhaust Gas Recirculation (EGR) System Check

EGR System Diagnosis:

PFI Emission Circuit:

DESCRIPTION:

Before starting check the 10 amp fuse #3 in the underhood relay center then measure the EGR solenoid resistance.

This engine uses a positive backpressure EGR valve which limits EGR flow with low exhaust backpressure (idle, decel, etc.). It is very important that exhaust tubes which decrease backpressure (pull air through) are not hooked to the vehicle when diagnosing the EGR system.

VACUUM TEST:

1. Connect a vacuum gauge to the source side or the EGR solenoid. Start the engine, manifold vacuum should be present. If it is not, repair leaks or obstruction between the EGR solenoid and throttle body.

2. Connect a vacuum gauge to the EGR valve vacuum supply. There should be no vacuum with the engine idling. If there is, follow Chart C-7.

3. With the gauge hooked to the EGR valve vacuum supply, disconnect the EGR solenoid connector. There should be more than 8 inches of vacuum available. If not, repair leak or obstruction in EGR valve vacuum hose.