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Manifold Absolute Pressure Sensor

  1. Check MAP sensor vacuum hose connections at throttle body and sensor. Test MAP sensor output voltage at MAP sensor connector pin B (as marked on sensor body) with the ignition switch ON and the engine OFF. Output voltage should be 4.0-5.0 volts.
    NOTE: Voltage should drop 0.5-1.5 volts with hot engine, at idle.
  2. Test pin 12 of ECU connector J2 for 4.0-5.0 volts to verify wiring harness condition.
  3. Check for MAP sensor supply voltage of 4.5-5.5 volts at sensor connector, pin C, with ignition ON. Similar voltage should be present at pin 2 of ECU connector J2. Repair or replace wiring harness if required. Test for sensor ground between pin 13 of ECU connector J2 and pin A of sensor connector.
  4. Check for ground from pin 13 of ECU connector J2 to pin F of connector J1. If an open circuit is indicated, check for a good sensor ground on the flywheel housing near the starter motor.
  5. If ground is good, the ECU must be replaced. Before replacing ECU, check to see if pin 13 of ECU connector J2 is shorted to 12 volts. If so, correct the condition before replacing ECU.
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