Manifold Absolute Pressure (MAP) Sensor (Except MFI - Calif &

New York)

1) A malfunction in the manifold absolute pressure sensor circuit will set diagnostic trouble Codes 31 and/or 32. For testing procedures, see TESTS W/CODES article in this section. Use the following procedure to diagnose MAP sensor. If driveability problems exist, MAP sensor failure is suspected and no Codes 31 and/or 32 is set, disconnect MAP sensor connector. If driveability improves, replace MAP sensor.

2) MAP sensor is located on firewall. With ignition on, check supply voltage from ECM to MAP sensor on designated wire terminal. See the MAP SENSOR WIRE TERMINAL IDENTIFICATION  table. Reading should be approximately 5 volts.

3) Disconnect vacuum hose at MAP sensor. Install hand-held vacuum pump. Turn ignition on. Check signal voltage at designated wire terminal of MAP sensor. See MAP SENSOR WIRE TERMINAL IDENTIFICATION  table.

4) Apply vacuum, and note change in signal voltage. As vacuum reading changes, signal voltage should change. Reading should be about 1-1.5 volts at high vacuum (idle position) to 4-4.5 volts at low vacuum (full throttle position).