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Home >> Saturn >> 2000 >> SW2 Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Testing & Engine Component Testing >> Engine Sensors & Switches >> Manifold Absolute Pressure Sensor >> 3.1L, 3.4L & 3.8L
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3.1L, 3.4L & 3.8L

  1. Check for the following conditions. If problem does not exist, go to next step. If problem exists, repair as necessary and go to step  13.
    • MAP sensor seal damaged or missing.
    • Vacuum hoses disconnected, damaged or incorrectly routed.
    • Intake manifold vacuum leaks.
    • Vacuum leak at throttle body.
    • Vacuum leaks in EGR system.
    • Faulty PCV system.
  2. Disconnect MAP sensor harness connector. Using scan tool, observe MAP sensor parameter. If scan tool displays zero volts, go to next step. If scan tool does not display zero volts, go to step  11.
  3. Using a test light connected to battery voltage, probe MAP sensor signal circuit (Light Green wire) at MAP sensor harness connector. Observe MAP sensor parameter. If scan tool displays 4.95 volts, go to next step. If scan tool does not display 4.95 volts, go to step  7.
  4. Connect a fused jumper wire between MAP sensor signal circuit (Light Green wire) and MAP sensor reference voltage circuit (Gray wire) at MAP sensor harness connector. Observe MAP sensor parameter. If scan tool displays 4.95 volts, go to next step. If scan tool does not display 4.95 volts, go to step  6.
  5. Turn ignition off. Disconnect PCM harness connectors. Check for an open or high resistance in MAP sensor ground circuit (Orange/Black wire or Black wire). Also, check for poor connections at PCM. If problem does not exist, go to step  9. If problem exists, repair as necessary and go to step  13.
  6. Check for an open or high resistance in MAP sensor reference voltage circuit (Gray wire). Also, check for poor connections at PCM. If problem does not exist, go to step  8. If problem exists, repair as necessary and go to step  13.
  7. Turn ignition off. Disconnect PCM harness connectors. Check for an open, high resistance or short to ground in MAP sensor signal circuit (Light Green wire). Also, check for poor connections at PCM. If problem does not exist, go to step  8. If problem exists, repair as necessary and go to step  13.
  8. Check for poor connection at MAP sensor signal circuit (Light Green wire) of PCM. If problem does not exist, go to step  12. If problem exists, repair as necessary and go to step  13.
  9. Check for poor connection at MAP sensor. If problem does not exist, go to next step. If problem exists, repair as necessary and go to step  13.
  10. Replace MAP sensor. After repairs, go to step  13.
  11. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Check for short to voltage in MAP sensor reference voltage circuit (Gray wire). If problem does not exist, go to next step. If problem exists, repair as necessary and go to step  13.
  12. Replace PCM. After repairs, go to next step.
  13. Start engine and let idle. While observing MAP sensor parameter on scan tool, increase engine RPM. If MAP sensor valve changes, system is okay. If MAP sensor valve does not change, go to step  1.
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