The black/white wire on the BAP/MAP sensor is the ground.
Code 22 MAP (vacuum) or BARO signal out of range. The MAP or BARO sensor is
pretty much the same sensor for both Mass Air & Speed Density cars. The main
difference is where it is connected. Mass Air cars vent it to the atmosphere, while
Speed Density cars connect it to the intake manifold vacuum. Its purpose is to help
set a baseline for the air/fuel mixture and changes in barometric pressure. The MAP
or BAP sensor puts out a 5 volt square wave that changes frequency with variations
in atmospheric pressure. The base is 154 HZ at 29.92" of mercury - dry sunny day
at sea level, about 68-72 degrees. You need an oscilloscope or frequency meter to
measure it.
Baro or MAP test using frequency meter - run the test key on engine off. The noise
from the ignition system will likely upset the frequency meter. I used a 10 x
oscilloscope probe connected from the frequency meter to the MAP/BAP to reduce
the jitter in the meter's readout.
If it is defective, your air/fuel ratio will be off and the car’s performance &
emissions will suffer.
See the following website for some help from Tmoss (diagram designer) &
Stang&2Birds (website host) for help on 88-95 wiring
http://www.veryuseful.com/mustang/tech/engine
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
Diagram courtesy of Tmoss & Stang&2birds