Getting a "P0021 - B2 A Cam Position Timiming System Perform" after replace of both Camshaft sensor

I just replaced 2 cam shaft sensors and the check engine light is back on. Had a friend read it today and we got a:
P0021 - B2 A-Cam Position timming System Perform
Any ideas on what might be causing this? thanks again, this forum is awesome

Can any one help on this
Can any one help on this please. have any one had this problem? how did you fix it?