Cadillac Repair: what do these codes mean, vehicle speed sensor, vehicle speed sensor vss

Question
I have a 92 cadillac deville 92, 4.9 engine. These codes are coming up, E52, E71, E75, and F48. Can you tell me what these codes mean?

Answer
E52 = battery was disconnected at some time in the past.
E71 = intermittent MANIFOLD ABSOLUTE PRESSURE SENSOR (MAP).
E75 = intermittent VEHICLE SPEED SENSOR (VSS).
F48 = Low freon in the AC system or faulty low pressure
     switch. Check to be sure using AC gages that you
     have the correct amount of freon in the system.

CLEAR (erase all the codes from the computer after you check the freon amount and see which codes return.