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Home >> Buick >> 2015 >> Verano Base >> Repair and Diagnosis >> Accessories & Equipment >> Entertainment Systems >> Cellular System, Entertainment System, And Navigation System >> Diagnostic Information and Procedures >> DTC B1278 or B1279: Auxiliary Input Signal Circuit >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the X1 harness connector at the X83 Auxiliary Audio Input. Ignition ON, radio ON.
  2. Test for less than 1 V between the signal circuits listed below and ground:
    • left auxiliary audio signal circuit terminal 1
    • right auxiliary audio signal circuit terminal 2
    • auxiliary audio common signal circuit terminal 3
    • If 1 V greater 
    1. Ignition OFF, disconnect the harness connector at the T11 Multimedia Player Interface Module. Ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the T11 Multimedia Player Interface Module.
    • If less than 1 V 
  3. Ignition OFF, disconnect the harness connector at the T11 Multimedia Player Interface Module.
  4. Test for infinite resistance between the signal circuits listed below and ground:
    • auxiliary audio common signal circuit terminal 3
    • left auxiliary audio signal circuit terminal 12
    • right auxiliary audio signal circuit terminal 13
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • If infinite resistance 
  5. Test for less than 5 Ω between the signal circuit terminals listed below:
    • T11 Multimedia Player Interface Module X1 terminal 3 and the X83 Auxiliary Audio Input X1 terminal 3
    • T11 Multimedia Player Interface Module X1 terminal 12 and the X83 Auxiliary Audio Input X1 terminal 1
    • T11 Multimedia Player Interface Module X1 terminal 13 and the X83 Auxiliary Audio Input X1 terminal 2
    • If 5 Ω greater 

      Repair the open/high resistance in the circuit.

    • If less than 5 Ω 
  6. Replace the X83 Auxiliary Audio Input. Connect all harness connectors.
  7. Connect and operate the EL-50334-20  Multi-Media Interface Tester (MIT).
  8. Verify DTC B1278 or DTC B1279 is not set.
    • If DTC B1278 or DTC B1279 is set 

      Replace the T11 Multimedia Player Interface Module.

    • If DTC B1278 or DTC B1279 is not set 
  9. All OK.