DTC P0400: EGR Excessive Or Insufficient Flow: Condition

DTC is set when intake manifold absolute pressure between when EGR valve is opened and closed is more or less than predetermined value when engine is at normal operating temperature and vehicle is decelerating. This circuit is monitored once per drive cycle. MIL is illuminated when Engine Control Module (ECM) detects malfunction during 2 consecutive drive cycles. Possible causes are:

• EGR valve malfunction.
• EGR circuit malfunction.
• EGR passage restricted.
• ECM malfunction.