DTC P0400: EGR Flow Malfunction: Condition
WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
DTC is set when intake manifold pressure is to high or to low when EGR is turn on and off. Possible causes are:
- EGR valve malfunction.
- EGR boost sensor malfunction.
- EGR boost solenoid valve malfunction.
- Restricted exhaust system.
- Faulty Powertrain Control Module (PCM).
- Short circuit in wiring harness.