Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 GMC Yukon AT4FACTORY OEM SERVICE PROCEDURE
Seat Belts
- Specifications
- Schematic Wiring Diagrams
- Diagnostic Information and Procedures
- DTC B191F
- Diagnostic Instructions
- DTC Descriptors
- Diagnostic Fault Information
- Circuit/System Description
- Conditions for Running the DTC
- Conditions for Setting the DTC
- Action Taken When the DTC Sets
- Conditions for Clearing the DTC
- Reference Information
- Circuit/System Verification
- Circuit/System Testing
- Repair Instructions
- DTC B1920
- Diagnostic Instructions
- DTC Descriptors
- Diagnostic Fault Information
- Circuit/System Description
- Conditions for Running the DTC
- Conditions for Setting the DTC
- Action Taken When the DTC Sets
- Conditions for Clearing the DTC
- Reference Information
- Circuit/System Verification
- Circuit/System Testing
- Repair Instructions
- DTC B1921
- Diagnostic Instructions
- DTC Descriptors
- Diagnostic Fault Information
- Circuit/System Description
- Conditions for Running the DTC
- Conditions for Setting the DTC
- Action Taken When the DTC Sets
- Conditions for Clearing the DTC
- Reference Information
- Circuit/System Verification
- Circuit/System Testing
- Repair Instructions
- DTC B1922
- Diagnostic Instructions
- DTC Descriptors
- Diagnostic Fault Information
- Circuit/System Description
- Conditions for Running the DTC
- Conditions for Setting the DTC
- Action Taken When the DTC Sets
- Conditions for Clearing the DTC
- Reference Information
- Circuit/System Verification
- Circuit/System Testing
- Repair Instructions
- DTC B1A32
- DTC B1AD2
- Diagnostic Instructions
- DTC Descriptors
- Diagnostic Fault Information
- Circuit/System Description
- Conditions for Running the DTC
- Conditions for Setting the DTC
- Action Taken When the DTC Sets
- Conditions for Clearing the DTC
- Reference Information
- Circuit/System Verification
- Circuit/System Testing
- Repair Instructions
- DTC B1AD3
- Diagnostic Instructions
- DTC Descriptors
- Diagnostic Fault Information
- Circuit/System Description
- Conditions for Running the DTC
- Conditions for Setting the DTC
- Action Taken When the DTC Sets
- Conditions for Clearing the DTC
- Reference Information
- Circuit/System Verification
- Circuit/System Testing
- Repair Instructions
- Symptoms - Seat Belts
- Seat Belt Does Not Retract
- Seat Belt Guide Adjuster Stuck in Full Down Position
- Seat Belt Retractor Does Not Function Properly or is Inoperative - Automatic Locking Retractor
- Seat Belt Retractor Does Not Function Properly or is Inoperative - Overspool Lock
- Seat Belt Retractor Does Not Function Properly or is Inoperative - Vehicle Sensing
- Seat Belt Retractor Does Not Function Properly or is Inoperative - Belt Sensing
- Seat Belt Retractor Does Not Function Properly or is Inoperative - Belt Twisting
- Seat Belt Retractor Does Not Function Properly or is Inoperative - Guide Contamination
- Noise Heard from Motorized Seat Belt Retractor
- Seat Belt Buckle Does Not Function Properly and/or Seat Belt Warning Lamp Illuminated
- Seat Belt Indicator Malfunction - Driver
- Seat Belt Indicator Malfunction - Passenger
- Seat Belt Service Precautions
- DTC B191F
- Repair Instructions
- Repairs and Inspections Required After a Collision
- Seat Belt Retractor Guide Cleaning
- Front Seat Belt Buckle Replacement
- Front Seat Belt Opening Bezel Replacement (Center Seat)
- Front Seat Center Belt Buckle Replacement
- Front Seat Center Belt Retractor Replacement
- Rear Seat Belt Buckle Replacement (40 Percent, Bucket with UH5)
- Rear Seat Belt Buckle Replacement (40 Percent, Bench Center Buckle without UH5)
- Rear Seat Belt Buckle Replacement (Bench Center Buckle with UH5)
- Rear Seat Belt Buckle Replacement (60 Percent with UH5)
- Rear Seat Belt Buckle Replacement (Bucket without UH5)
- Rear Seat Belt Buckle Replacement (60 Percent without UH5)
- Rear Seat Center Belt Retractor Replacement
- Front Seat Belt Guide Adjuster Replacement
- Rear Seat Belt Retractor Replacement
- Rear Seat Center Belt Opening Bezel Replacement
- Rear Seat Center Belt Opening Bezel Replacement (3rd Row)
- 3rd Row Seat Belt Buckle Replacement (60 Percent and Mini Buckle)
- 3rd Row Seat Belt Buckle Replacement (40 Percent and Center Buckle)
- 3rd Row Center Seat Belt Retractor Replacement (SWB)
- 3rd Row Center Seat Belt Retractor Replacement (LWB)
- 3rd Row Seat Belt Retractor Replacement
- Description and Operation
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.