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Home >> Oldsmobile >> 2002 >> Bravada AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 4.2L >> Diagnostic Tests >> DTC P0105: Map System Performance >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Inspect for the following conditions:
    • MAP sensor seal missing or damaged.
    • Restrictions in the MAP sensor vacuum source.
    • Vacuum hoses disconnected, damaged, or incorrectly routed.
    • Vacuum leaks between the intake manifold and the engine.
    • Vacuum leaks at the throttle body.

    Did you find and correct the condition? If yes, go to step  22 . If no, go to next step.

  3. Install a scan tool. Turn ON the ignition, with the engine OFF. Monitor the scan tool and record the MAP sensor pressure. Compare the MAP sensor pressure to that of a known-good vehicle. Is the pressure difference between the vehicles less than 3 kPa? If yes, go to next step. If no, go to step  8 .
  4. Observe the MAP sensor pressure on the scan tool. Start the engine. Does the MAP sensor value change? If yes, go to next step. If no, go to step  8 .
  5. Turn OFF the ignition. Remove the MAP sensor from the vacuum source. Leave the electrical harness connected. Connect a hand vacuum pump to the MAP sensor. Turn ON the ignition, with the engine OFF. Observe the MAP sensor pressure as you SLOWLY apply vacuum 1 in. Hg at a time. Each inch of vacuum should result in a 3-4 kPa drop in the MAP sensor pressure. Increase the vacuum to 20 in. Hg. Does the scan tool indicate that the MAP sensor pressure decreases smoothly through the test? If yes, go to next step. If no, go to step  18 .
  6. Observe the MAP sensor pressure with 20 in. Hg of vacuum applied to the MAP sensor. Does the scan tool indicate that the MAP sensor pressure is less than 34 kPa? If yes, go to next step. If no, go to step  8 .
  7. Disconnect the MAP sensor from the hand vacuum pump. Does the MAP sensor pressure return to the original value that was observed in step  3 ? If yes, see DIAGNOSTIC AIDS  . If no, go to step  18 .
  8. Turn OFF the ignition. Disconnect the MAP sensor electrical connector. Turn ON the ignition, with the engine OFF. Does the scan tool indicate that the MAP sensor voltage is more than 0.3 V? If yes, go to step  17 . If no, go to next step.
  9. Probe the 5-volt reference circuit of the MAP sensor with a test lamp that is connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step  16 .
  10. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the MAP sensor and the signal circuit of the MAP sensor. Does the scan tool indicate that the MAP sensor voltage is near 5 V? If yes, go to next step. If no, go to step  15 .
  11. Remove the jumper wire. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground. Does the voltage measure more than 5.2 V? If yes, go to step  13 . If no, go to next step.
  12. Probe the low reference circuit of the MAP sensor with a test lamp that is connected to battery voltage. Does the test lamp illuminate? If yes, go to step  18 . If no, go to step  14 .
  13. Test the 5-volt reference circuit of the MAP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  22 . If no, go to step  19 .
  14. Test the low reference circuit of the MAP sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step  22 . If no, go to step  19 .
  15. Test the signal circuit of the MAP sensor for high resistance. Did you find and correct the condition? If yes, go to step  22 . If no, go to step  19 .
  16. Test the 5-volt reference circuit of the MAP sensor for high resistance. Did you find and correct the condition? If yes, go to step  22 . If no, go to step  19 .
  17. Test the signal circuit of the MAP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  22 . If no, go to step  19 .
  18. Inspect the MAP sensor for poor connections. Did you find and correct the condition? If yes, go to step  22 . If no, go to step  20 .
  19. Inspect the PCM for poor connections. Did you find and correct the condition? If yes, go to step  22 . If no, go to step  21 .
  20. Replace the MAP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  22 .
  21. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  22. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2 .
  23. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no, system is okay.
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