P0400 Exhaust Gas Recirculation Flow Malfunction: Causes, Cleaning, and Repair
P0400 indicates that the powertrain control module detected an EGR flow rate that does not match expected values during the EGR system self-test. The exhaust gas recirculation (EGR) system routes a measured quantity of exhaust gas back into the intake manifold to dilute the incoming air-fuel mixture. This dilution reduces peak combustion temperatures, which lowers […]