1996 Dodge Caravan Code P0106

Computer problem
1996 Dodge Caravan 4 cyl Two Wheel Drive Automatic 103, 00 miles

I recently had the catalytic converter replaced with a magnaflow direct fit cat converter. After driving a few miles I got :service engine soon" and in checking with my scaner got a P0106 code which in my shop service manual indicates "MAP sensorhas a bao reading below an accepatable level". Never having got this code before I am assuming that the problem is the result of changing the converter. Assuming that the MAP sensor is not at fault problem what should I look for as being the problem?