Vacuum Test

Test Number 1)  Connect vacuum gauge to source side of EGR solenoid. Start engine. Manifold vacuum should be present. If not, repair leaks or obstruction between EGR solenoid and throttle body.

Test Number 2)  Connect vacuum gauge to EGR valve vacuum supply hose. There should be no vacuum with engine idling. If there is vacuum, go to ECM CODE EO48 (Cont.).

Test Number 3)  With gauge hooked to EGR valve vacuum supply hose, disconnect EGR solenoid connector. With engine idling, vacuum reading should be greater than 8 in. Hg. If not, repair leak or obstruction in EGR valve vacuum hose.