2001 Nissan Altima P0400 Code: How to Fix After Replacing EGV Valve
My 2001 Nissan Altima is showing a P0400 diagnostic trouble code, and even after replacing the EGR valve (EGV), the code persists. I need to pass smog inspection but the check engine light remains on. What other components should I inspect or replace to clear this code? Any specific steps for diagnosing the P0400 issue in a 2001 Nissan Altima?
Check the EGR solenoid and vacuum lines to ensure proper vacuum connection to the EGR when commanded. Also verify fuse #25 (10 amp) in the fuse box or junction block, as a blown fuse can cause P0400 to remain active.