diagnostic code p0401 egr flow insufficent ? on 1998 Buick Century

diagnostic code p0401 egr flow insufficient making check engine light come on . what is the cause.

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1 answer 1 comment
usually a clogged vaccuum port in throttle body.
if they are clear, the valve may be bad. have it checked to verify.

Roy
THANK YOU I WILL CHECK THAT.