Manifold Absolute Pressure (Map) Sensor

Inspect MAP sensor vacuum hose connections at sensor and throttle body. Repair as required. Test MAP sensor output voltage at MAP sensor connector pin B (as marked on sensor body) with the ignition switch "ON" and engine off. See Figure . Output voltage should be 4.0-5.0 volts.
NOTE: Voltage should drop 0.5-1.5 volts with hot engine, at idle.

Fig 1: MAP Sensor Terminal Identification If markings on MAP sensor vary from illustration, use markings on sensor.
Test voltage at pin 33 of ECU connector for 4.0-5.0 volts to verify wiring harness condition. Repair if required.
With ignition on, check for MAP sensor supply voltage of 4.5-5.5 volts at sensor connector pin C. Similar voltage should be present at pin 16 of ECU connector. Repair or replace wiring harness if required. Test for sensor ground between pin 17 of ECU connector and pin A of sensor connector.
Using an ohmmeter, check for ground from pin 17 of ECU connector to pin 2. If an open circuit is indicated, check for a defective sensor ground on the flywheel housing near the starter motor.
If ground is good, the ECU must be replaced. Before replacing ECU, check to see if pin 17 of ECU connector is shorted to 12 volts. If so, correct the condition and test ECU before replacing. Refer to the ELECTRONIC CONTROL UNIT TEST .