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Home >> Buick >> 2009 >> Allure CX >> Repair and Diagnosis >> Electrical >> Charging Systems >> Battery, Charging System And Starting System >> Diagnostic Information and Procedures >> DTC B1420 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF. Disconnect the harness connectors at the BCM.
  2. Ignition OFF, test for less than 5.0 ohms between the BCM ground circuit terminals listed below and ground.
    • Terminal 17 X1
    • Terminal 19 X1
    • Terminal 20 X1
    • Terminal 50 X2
    • If greater than the specified value, test the ground circuits for an open/high resistance.
  3. Ignition ON, verify a test lamp between the B+ / IGN circuits terminals listed below and ground.
    • Terminal 46 X1
    • Terminal 50 X1
    • Terminal 51 X1
    • Terminal 52 X1
    • Terminal 3 X1
    • Terminal 22 X1
    • Terminal 23 X1
    • If the test lamp does not illuminate, test the B+ / IGN circuits for a short to ground or an open/high resistance.
  4. If all the circuits test normal, replace the BCM.