Pcm Code E048, EGR System Fault (1 Of 2): Description

To perform test, PCM turns off EGR flow to engine and monitors O2 sensor ("closed loop") integrator. With EGR off, integrator should swing to a greater value, reflecting leaner air/fuel mixtures. If integrator does not swing to a greater value, PCM assumes either EGR was turned off before test started or EGR is flowing and PCM does not have ability to turn it off. PCM tests EGR 5 times in a given key cycle. If EGR does not respond 3 or more times during a key cycle, PCM Code E048 is set.