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scottylt1scottylt1 NC Posts: 1
edited January 2019 in Buick
Hello All, I am new to this site and I’m hoping for some help! I have searched all over the internet and have had no luck. So I have a 99 Buick century custom throwing code P0401 so I go for the egr valve took it off and there is a tan/brown sludge type of stuff in there. Any ideas on what’s causing this or what the solution is to fix? Looked everywhere and can’t find any concrete information. Thank you for any help you may be able to provide.


  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 25,551
    Is the valve filled with this stuff where the goop is blocking EGR flow?

    I'd take a wire and try to break it loose and out. I'd clear the tubes to the EGR.

    You can clean the EGR moving part with solvents but don't get any in the top with the electrical
    connections. I used gasoline in a vegetable can to soak the bottom part. Sometimes the valves
    stick open, but that's not what your code is indicating.

    There are other things that can cause that insufficient flow of EGR gases code, too.

    2014 Malibu 2LT, 2015 Cruze 2LT,

  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    clogged or restricted EGR passages
    faulty EGR valve
    EGR valve stuck closed
    clogged catalytic converter
    carboned up EGR temperature sensor
    vacuum supply issues at the vacuum-operated EGR valve
    electrical problems with the EGR valve control circuit
    engine computer problems
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