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Home › GMC › 2021 › Acadia SL › Repair and Diagnosis › External Pages › Different car › Section 160 (Cellular, Entertainment, And Navigation System) › Diagnostic Information and Procedures › DTC B127E › Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2020 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.
  1. Vehicle OFF/Ignition OFF.
  2. Disconnect the X1 harness connector at the P17 Info Display Module. It may take up to 2 min for all vehicle systems to power down.
  3. Test for less than 10 Ω between the ground circuit terminal 8 and ground.
    • If 10 Ω or greater 
    1. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 Ω 
  4. Verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.
    • If the test lamp does not illuminate and the fuse is good 
    1. Vehicle OFF/Ignition OFF
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify there is voltage at the fuse. Refer to Power Mode Mismatch
    • Go to next step: If the test lamp illuminates 
  5. Reconnect harness connector X1 at the P17 Info Display Module.
  6. Verify the LVDS interface cable is properly connected at the P17 Info Display Module and the A11 Radio and there is no damage to the cable or connections.
  7. Ignition ON/Vehicle in Service Mode, infotainment system ON.
  8. Verify the P17 Info Display Module displays an image.
    • If the P17 Info Display Module does not display an image. 

      Replace LVDS interface cable from the P17 Info Display Module to the A11 Radio.

    1. Ignition ON/Vehicle in Service Mode, infotainment system ON.
    2. Verify the P17 Info Display Module displays an image.
      • If the P17 Info Display Module does not display an image.

        Replace the P17 Info Display Module.

    3. Ignition ON/Vehicle in Service Mode, infotainment system ON.
    4. Verify the P17 Info Display Module displays an image.
      • If the P17 Info Display Module does not display an image.

        Replace the A11 Radio.

      • Go to next step: If the P17 Info Display Module displays an image

        Go to next step: All OK.

    • Go to next step: If the P17 Info Display Module displays an image. 
  9. All OK.
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