Question Asked: Why did 1998 ML320 fail emissions test twice?
October 04, 2010, 10:01 AM
On 8-21-10 my SUV failed the first emissions test. It gave codes P0100 Mass Air Flow Circuit Malf and P0400 Exhaust Gas Recirculation Flow Malf. On 9-13-10 Cleaned EGR valve and ports. On 9-24-10 replaced Mass Air Flow Sensor. 9-24-10 check engine light came back on, code P0400 EGR showed up again.