DTC P0402: EGR System, Excessive Flow: Condition
WARNING: This page is about a different car, the 2002 Mazda Protege5 and 2002 Mazda Protege. However, it is still accessible from the selected car via links, so may be relevant.
DTC is set when the difference in intake manifold pressures between open EGR and closed EGR is too large. This is an intermittent monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are:
- EGR valve base gasket damaged or missing.
- PCM malfunction.