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Home >> Chevrolet >> 2018 >> Traverse LS, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1 (HVAC - Automatic) >> Diagnostic Information and Procedures >> DTC B048D >> Circuit/System Testing

Circuit/System Testing

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  1. Ignition OFF, disconnect the X2 harness connector at the E40 Electrical Auxiliary Heater. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal 2 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. 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 
  3. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    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 the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF, remove the test lamp.
    2. Test for infinite resistance between the B+ circuit terminal 1 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the E40 Electrical Auxiliary Heater.
    • Go to next step: If the test lamp illuminates 
  4. Ignition OFF, remove the test lamp and disconnect the X1 harness connector at the E40 Electrical Auxiliary Heater, ignition ON.
  5. Verify a test lamp illuminates between the ignition circuit terminal 2 X1 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    2. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF, remove the test lamp.
    2. Test for infinite resistance between the ignition circuit terminal 2 X1 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the E40 Electrical Auxiliary Heater.
    • Go to next step: If the test lamp illuminates 
  6. Ignition OFF, remove the test lamp and disconnect the X2 harness connector at the K33 HVAC Control Module, ignition ON.
  7. Test for less than 1 V between the control circuit terminal 7 X2 at the K33 HVAC Control Module harness connector and ground.
    • If greater than 1 V 

      Repair the short to voltage on the circuit.

    • Go to next step: If less than 1 V 
  8. Ignition OFF.
  9. Test for infinite resistance between the control circuit terminal 7 X2 at the K33 HVAC Control Module harness connector and ground.
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • Go to next step: If infinite resistance 
  10. Test for less than 2 Ω between the K33 HVAC Control Module control circuit terminal 7 X2 and control circuit terminal 1 X1 at the E40 Electrical Auxiliary Heater harness connector.
    • If greater than 2 Ω 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 Ω 
  11. Replace the E40 Electrical Auxiliary Heater and verify the DTC does not reset.
    • If DTC resets 

      Replace the K33 HVAC Control Module.

    • Go to next step: If DTC does not reset 
  12. All OK.
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