04 Ion2 getting OBD codes/bad mileage

This car has been reliable except the CD changer but now I am getting 15 miles per gallon all of a sudden.

I hooked up the Centech OBDII reader and got:

P0200 Injector circuit open
P0004 Fuel Voltage Regulator Circuit High
P0602 Program Control Module Error

Then the following which have NO description:

B2500
P00FB
B2BAA
P0B49
P0000 (I think this just means there are codes)

I know "B" refers to the body/chassis which really surprises me, but if anyone can provide info on the mysterious ones or knows what the prob may be your help is appreciated.

Since it is the fuel system and PCM I am thinking bad computer(s), which I hope not. Thanks in advance.:eek7:

P0200 has a GM bulletin about the injector control circuit chaffing and shorting to ground on the AC line bracket on the rear of the head, above the transmission. Not sure if that will fix it or not, but just letting you know there is a GM bulletin so its pretty common. P0602 means you need to reprogram your TCM, and if your TCM will not reprogram, or programs but P0602 comes back, you need to replace the TCM. All the other codes are not even showing up on the GM service manual. I would start with the P0200 and P0602 to begin with though. Several wires run thru that harness stated in the bulletin and the TCM completes a circuit to many components as well. Hope this helps!