EGR P0405 err mssg.

Hi to everyone who can help me.

I have a Chevy Tahoe 1999.
At the last emission test I received a code error P0405 EGR Senzor A Circuit Low.
I replaced the EGR valve wit a new one and I received the same error message.
There is any one who can tell me what shoud I do to fix this problem?
My email address is: [email protected]
Thanks in advance

Maur