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HOMESERVICE MANUALSCHEVROLET2018SILVERADO 2500 HD WT, 2D PICKUP, 6.0L ENG VIN G, RWD, GASREPAIR AND DIAGNOSISBRAKESBRAKES CONTROL SYSTEMSTRAILER BRAKE CONTROLS SYSTEMDIAGNOSTIC INFORMATION AND PROCEDURESTRAILER CONNECTION NOT RECOGNIZEDCIRCUIT/SYSTEM TESTING
2018 Chevrolet Silverado 2500 HD WT, 2D Pickup, 6.0L Eng VIN G, RWD, Gas

Circuit/System Testing

2018 Chevrolet Silverado 2500 HD WT, 2D Pickup, 6.0L Eng VIN G, RWD, GasSECTION Circuit/System Testing
NOTE:
  • You must perform the Circuit/System Verification before proceeding with the Circuit/System Testing. 
  • The following diagnostic procedure is for factory installed components and wiring on the customer's vehicle. It will not diagnose a concern with the components and wiring on the customer's trailer. 
  • The following diagnostic procedure is based on not having a trailer connected to the vehicle.
  • Refer to PIT5311 for additional information before using this diagnostic procedure.
  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the K133 Trailer Brake Power Control Module. 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 9 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. Ignition ON.
  4. 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 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K133 Trailer Brake Power Control Module.
    • Go to next step: If the test lamp illuminates 
  5. Ignition OFF, disconnect the harness connector at the K38A Chassis Control Module-Auxiliary, ignition ON.
  6. Test for less than 1 V between the signal circuit terminals listed below and ground:
    • K133 Trailer Brake Power Control Module signal circuit terminal 2
    • K133 Trailer Brake Power Control Module signal circuit terminal 5
    • K133 Trailer Brake Power Control Module signal circuit terminal 8
    • K133 Trailer Brake Power Control Module signal circuit terminal 12
    • K133 Trailer Brake Power Control Module signal circuit terminal 14 (if equipped with this wire)
    • If 1 V or greater 

      Repair the short to voltage on the circuit.

    • Go to next step: If less than 1 V 
  7. Ignition OFF.
  8. Test for infinite resistance between the signal circuit terminals listed below and ground:
    • K133 Trailer Brake Power Control Module signal circuit terminal 2
    • K133 Trailer Brake Power Control Module signal circuit terminal 5
    • K133 Trailer Brake Power Control Module signal circuit terminal 8
    • K133 Trailer Brake Power Control Module signal circuit terminal 12
    • K133 Trailer Brake Power Control Module signal circuit terminal 14 (if equipped with this wire)
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • Go to next step: If infinite resistance 
  9. Test for less than 2 Ω between the signal circuit terminals listed below:
    • K133 Trailer Brake Power Control Module signal circuit terminal 2 and the K38A Chassis Control Module-Auxiliary signal circuit terminal 23
    • K133 Trailer Brake Power Control Module signal circuit terminal 5 and the K38A Chassis Control Module-Auxiliary signal circuit terminal 22
    • K133 Trailer Brake Power Control Module signal circuit terminal 12 and the K38A Chassis Control Module-Auxiliary signal circuit terminal 30
    • K133 Trailer Brake Power Control Module signal circuit terminal 14 and the K38A Chassis Control Module-Auxiliary signal circuit terminal 17 (if equipped with this wire)
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 Ω 
  10. Test for less than 2 Ω between the K133 Trailer Brake Power Control Module signal circuit terminal 8 and the Electric Brakes terminal in the trailer brake harness connector in the rear bumper. Refer to the diagram on the trailer brake harness connector cover for the terminal location.
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 Ω 
  11. Test or replace the K133 Trailer Brake Power Control Module.
  12. Verify the DTC does not set while operating the vehicle within the Conditions for Running the DTC.
    • If the DTC sets 

      Replace the K38A Chassis Control Module-Auxiliary.

    • Go to next step: If the DTC does not set 
  13. All OK.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.