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Home >> Pontiac >> 2007 >> Grand Prix Base >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Data Communication System >> Diagnostic Information and Procedures >> DTC B1390 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the ignition switch.
  2. Test for 11.8-12.2 volts between the 12-volt reference circuit terminal 6 and ground.
    • If less than the specified range, test the 12-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
    • If greater than the specified range, test the 12-volt reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  3. Test for 11.8-12.2 volts between the 12-volt reference circuit terminal 4 and ground.
    • If less than the specified range, test the 12-volt reference circuit for a short to ground or an open/high resistance.
    • If greater than the specified range, test the 12-volt reference circuit for a short to voltage.
  4. Connect the harness connector at the ignition switch.
  5. Disconnect the harness connector C1 at the BCM.
  6. Install a jumper wire between the 12-volt reference circuit terminal 25 and the 12-volt reference circuit terminal in the BCM.
  7. With the ignition in the OFF position, test for 0 volts at the following circuit terminals:
    • Ignition 1 circuit terminal 22
    • Ignition 3 circuit terminal 23
    • Crank voltage circuit terminal 21
    • If greater than 0 volts, test the applicable circuit for a short to voltage. If all circuits test normal, test or replace the ignition switch.
  8. With the ignition in the ACCY position, test for 11.8-12.2 volts at the ignition 3 circuit terminal 23.
    • If less than the specified range, test the ignition 3 circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the ignition switch.
    • If greater than the specified range, test the ignition 3 circuit for a short to voltage. If the circuit tests normal, replace the ignition switch.
  9. With the ignition in the RUN position, test for 11.8-12.2 volts at the follow circuit terminals:
    • Ignition 1 circuit terminal 22
    • Ignition 3 circuit terminal 23
    • If less than the specified range, test the applicable circuit for a short to ground or an open/high resistance. If the circuits test normal, test or replace the ignition switch.
    • If greater than the specified range, test the applicable circuit for a short to voltage. If the circuit tests normal, replace the ignition switch.
  10. With the ignition in the CRANK position, test for 11.8-12.2 volts at the crank voltage circuit terminal 21.
    • If less than the specified range, test the crank voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the ignition switch.
    • If greater than the specified range, test the crank voltage circuit for a short to voltage. If the circuit tests normal, test or replace the ignition switch.
  11. If all circuits test normal, test or replace the BCM.
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