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Home >> Chevrolet >> 2016 >> Suburban 3500 HD LS >> Repair and Diagnosis >> External Pages >> Different car >> Section 18 (Immobilizer System) >> Diagnostic Information and Procedures >> DTC P1649: Immobilizer Security Code Not Programmed >> Circuit/System Verification
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Circuit/System Verification

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2015 GMC Yukon XL, 2015 GMC Yukon, 2015 Chevrolet Tahoe, 2015 Chevrolet Suburban, and 2015 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify there are no immobilizer DTCs set in the K9 Body Control Module.
    • If no immobilizer DTCs are set in the K9 Body Control Module 
  2. Perform the K20 Engine Control Module immobilizer learn using the engine control module IMMO Learn in SPS. Refer to Immobilizer System Component Programming (without BTM) Immobilizer System Component Programming (with BTM) .
  3. Verify the engine starts after the K20 Engine Control Module completes the learn procedure.
    • If the engine does not start 

      Replace the K20 Engine Control Module.

    • If the engine starts 
  4. All OK.
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