DTC P0402: EGR System, Excessive Flow: Condition

DTC is set when the difference in intake manifold pressure between open EGR and closed EGR is too large. This is an intermittent monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are:

• EGR valve base gasket damaged or missing.
• Powertrain Control Module (PCM) malfunction.