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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 92 (Engine Controls - Self-Diagnostics - 6.6L Diesel) >> Diagnostic Tests >> DTC P0106: BARO System Performance (Ca) >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  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. Turn OFF the ignition. Inspect the BARO sensor for a plugged port. Did you find and correct the condition? If yes, go to step  22. If no, go to next step.
  3. Start the engine. Allow the engine to reach operating temperature. Turn OFF the ignition. Turn ON the ignition, with the engine OFF. Observe the BARO sensor pressure and the EGR vacuum sensor pressure with a scan tool. Is the difference between the sensors more than 10 kPa? If yes, go to step  7. If no, go to next step.
  4. Start the engine. Command the EGR duty cycle to 0 percent with a scan tool. Observe the BARO sensor pressure and the EGR vacuum sensor pressure with the scan tool. Is the difference between the sensors more than 10 kPa? If yes, go to step  12. If no, go to next step.
  5. Turn OFF the ignition. Connect a hand vacuum pump to the BARO sensor port. Turn ON the ignition, with the engine OFF. Monitor the BARO sensor pressure with the scan tool. Apply vacuum SLOWLY 1 in. Hg at a time. Each inch of vacuum should result in a 3-4 kPa drop in the BARO sensor pressure. Increase the vacuum to 20 in. Hg. Does the BARO sensor pressure decreases smoothly through the test? If yes, go to next step. If no, go to step  7.
  6. Disconnect the hand vacuum pump from the BARO sensor port. Does the BARO sensor pressure return to the original value that was observed in step  3? If yes, see DIAGNOSTIC AIDS . If no, go to step  20.
  7. Turn OFF the ignition. Disconnect the BARO sensor electrical connector. Turn ON the ignition, with the engine OFF. Does the BARO sensor pressure measure more than 44 kPa? If yes, go to step  17. If no, go to next step.
  8. Connect a test lamp to a good ground. Probe the 5-volt reference circuit of the BARO sensor with the test lamp. Perform a voltage drop test across the test lamp with a Digital Multimeter (DMM). Does the voltage measure more than 4.4 V? If yes, go to next step. If no, go to step  16.
  9. Does the voltage measure more than 5.2 V? If yes, go to step  13. If no, go to next step.
  10. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the BARO sensor and the signal circuit of the BARO sensor. Does the BARO sensor pressure measure more than 110 kPa? If yes, go to next step. If no, go to step  15.
  11. Connect a test lamp to battery positive voltage. Probe the low reference circuit of the BARO sensor with the test lamp. Does the test lamp illuminate? If yes, go to step  18. If no, go to step  14.
  12. Inspect for the following conditions:
    • Misrouted vacuum lines.
    • A skewed EGR vacuum sensor.

    Repair as necessary. After repairs, go to step  22.

  13. Test the 5-volt reference circuit of the BARO sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  22. If no, go to step  21.
  14. Test the low reference circuit of the BARO 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 BARO sensor for the following conditions:
    • A short to ground.
    • An open.
    • High resistance.

    Repair as necessary. 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 BARO sensor for the following conditions:
    • A short to ground.
    • An open 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 BARO sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  22. If no, go to step  21.
  18. Inspect the BARO 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 ECM 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 BARO sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  22.
  21. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See ENGINE 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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