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Home >> Buick >> 2012 >> Enclave AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls/Fuel - 3.6L - DTC P0340 To DTC P2635 And Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC P2199 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the B75C multifunction intake air sensor.
  2. Ignition OFF, all systems OFF. It may take up to for 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the low reference circuit terminal 3 and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition OFF, all vehicle systems OFF, test for less than 5 Ω between the ground circuit terminal 7 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool IAT Sensor 1 parameter is colder than -39°C (-38°F).
    • If warmer than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON. Test for 4.8-5.2 V between the IAT sensor 1 signal circuit terminal 1 and ground.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
      • NOTE:

      If the signal circuit is shorted to a voltage the ECM or the sensor may be damaged.

    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
  6. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 5 and ground.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
    • If the circuit tests normal and the fuse is open, test all the components connected to the circuit and repair or replace as necessary.
  7. Ignition ON, test for 4.8-5.2 V between the IAT sensor 2 signal circuit terminal 8 and ground.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
      • NOTE:

      If the signal circuit is shorted to a voltage the ECM or the sensor may be damaged.

    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  8. Ignition OFF, connect the red lead of the J 38522  variable signal generator to the signal circuit terminal 8 at the harness connector. Connect the battery voltage supply to B+, and the black lead to ground.
  9. Set the J 38522  variable signal generator to the following specifications:
    • Signal switch to 5 V
    • Duty Cycle switch to 50 % (Normal)
    • Frequency switch to 30 Hz
  10. Ignition ON, observe the scan tool IAT Sensor 2 parameter. The scan tool parameter should be between 28-32 Hz.
    • If the parameter is not within the specified range, replace the K20 ECM.
  11. If all circuits test normal, test or replace the B75C multifunction intake air sensor.
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