Circuit/System Testing

2025 Chevrolet Tahoe Commercial, 4WDSECTION Circuit/System Testing

Key Card Malfunction

  1. Ignition/Vehicle OFF, disconnect the K300 Near Field Communication Exterior Module.
  2. Disconnect the K300 Near Field Communication Exterior Module and test for less then 2 Ω between ground circuit terminal 3 and ground
    • If greater than 2 Ω 
    1. Repair the open/high resistance in the circuit.
    • Go to next step: If less than 2 Ω 
  3. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground.
    • If the test lamp does not illuminate 
    1. Remove fuse F22DA at the X51A Instrument Panel Wiring Harness Junction Block and test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    2. Test B+ circuit for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit
      • If an open/high resistance is not found, verify there is voltage present at fuse F22DA
    • Go to next step: If the test lamp illuminates 
  4. Ignition/Vehicle OFF, disconnect the K183 UHF Short Range Low Energy Remote Control Access Transceiver.
  5. Test for less than 2 ohms in the LIN circuit end to end between terminal 1 at the K300 Near Field Communication Exterior Module and terminal 1 at the K183 UHF Short Range Low Energy Remote Control Access Transceiver.
    • If greater than 2 Ω 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 Ω 
  6. Ignition ON/Vehicle in Service Mode, verify a test lamp illuminates between the B+ circuit terminal 20 of the K183 UHF Short Range Low Energy Remote Control Access Transceiver and ground.
    • If the test lamp does not illuminate 
    1. Remove fuse F22DA at the X51A Instrument Panel Wiring Harness Junction Block and test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    2. Test B+ circuit for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit
      • If an open/high resistance is not found, verify there is voltage present at fuse F22DA
    • Go to next step: If the test lamp illuminates 
  7. Test for less then 2 Ω between ground circuit terminal 18 at the K183 UHF Short Range Low Energy Remote Control Access Transceiver and ground.
    • If greater than 2 Ω 
    1. Repair the open/high resistance in the circuit.
    • Go to next step: If less than 2 Ω 
  8. Attempt to learn a new Key Card to the vehicle.
    • If a new Key Card is unable to be learned to the vehicle 

      Replace the K300 Near Field Communication Exterior Module.

    • If a new Key Card is able to be learned to the vehicle but vehicle access is still prohibited 

      Replace the K183 UHF Short Range Low Energy Remote Control Access Transceiver.

RENDER: 1.0x

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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.