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HOMESERVICE MANUALSCHEVROLET2020TAHOE LS, 4WD, GAS/ETHANOLREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTANTI-THEFT SYSTEMSTHEFT DETERRENT SYSTEMDIAGNOSTIC INFORMATION AND PROCEDURESDTC B291BCIRCUIT/SYSTEM TESTING
2020 Chevrolet Tahoe LS, 4WD, Gas/Ethanol

Circuit/System Testing

2020 Chevrolet Tahoe LS, 4WD, Gas/EthanolSECTION Circuit/System Testing
  1. Ignition OFF and vehicle systems OFF, disconnect the harness connector at the B165 Content Theft Deterrent Sensor 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 5 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 3 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    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 OK and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    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 B165 Content Theft Deterrent Sensor Module.
    • Go to next step: If the test lamp illuminates 
  5. Ignition OFF, arm the content theft deterrent system.
  6. Test for greater than 4.5 V between the serial data circuit terminal 4 and ground.
    • If 4.5 V or less 
    1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the serial data circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the serial data circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • Go to next step: If greater than 4.5 V 
  7. Ignition OFF, disconnect the harness connector at the K9 Body Control Module and any other components or control modules sharing the serial data circuit with the B165 Content Theft Deterrent Sensor Module, ignition ON.
  8. Test for less than 1 V between the B165 Content Theft Deterrent Sensor Module serial data circuit terminal 4 and ground.
    • If 1 V or greater 

      Repair the short to voltage on the circuit.

    • Go to next step: If less than 1 V 
  9. Test or replace the B165 Content Theft Deterrent Sensor Module.
  10. Fully arm then disarm the content theft deterrent system and verify no DTCs are set.
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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.