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Home >> Cadillac >> 2021 >> XT5 Sport >> Repair and Diagnosis >> External Pages >> Different car >> Section 734 (Keyless Entry System And Remote Functions) >> Diagnostic Information and Procedures >> DTC B3121 >> Circuit/System Verification
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Circuit/System Verification

WARNING: This page is about a different car, the 2023 GMC Sierra 3500 HD and 2023 GMC Sierra 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition - On/Vehicle - In Service Mode
  2. Verify no other DTCs are set.
    • Go to next step: If no DTC is set 
  3. Refer to Circuit/System Testing.