Cutlass V6-260 4.3L DSL (1984)
Fig. 023 - Chart For MAP Sensor Check.
1.
Checks for V-ref. at MAP sensor harness. Normal voltage at Terminal "C" of MAP harness should be about 5 volts.
2.
Checks for an open to ground in the MAP circuit to the ECM. Normal voltage is about 5 volts with a good ground.
3.
Checks for proper circuit from the MAP signal wire to ECM Terminal "B". High voltage (about V-ref.) indicates an open ECM terminal or ECM.
Low voltage is an open or grounded wire, or faulty MAP sensor.