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Home >> Geo >> 1995 >> Prizm Base, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Engine Controls - System/Component Tests - 1.8L) >> Computerized Engine Controls >> Engine Sensors & Switches >> Manifold Absolute Pressure (MAP) Sensor
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Manifold Absolute Pressure (MAP) Sensor

WARNING: This page is about a different variant/trim than selected.
  1. A malfunction in the manifold absolute pressure sensor circuit will set DTC 31. For testing procedures, see TESTS W/CODES - 1.8L article. Use the following procedure to diagnose MAP sensor. If driveability problems exist, MAP sensor failure is suspected and no DTCs 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 WIRING DIAGRAM  section at the end of this article. 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 WIRING DIAGRAM  section at the end of this article.
  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).
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