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.
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HOMESERVICE MANUALSGMC2021SIERRA 2500 HD AT4, 6.6L ENG VIN 7REPAIR AND DIAGNOSISBODY & FRAMEIGNITION SWITCH/STEERING LOCKIMMOBILIZER SYSTEM
2021 GMC Sierra 2500 HD AT4, 6.6L Eng VIN 7
Immobilizer System
2021 GMC Sierra 2500 HD AT4, 6.6L Eng VIN 7SECTION Immobilizer System
- Specifications
- Schematic Wiring Diagrams
- Diagnostic Information and Procedures
- Repair Instructions
- Theft Deterrent Module Replacement (without BTM)
- Theft Deterrent Module Replacement (with BTM and Front Floor Console)
- Theft Deterrent Module Replacement (with BTM and Front Center Seat)
- Immobilizer System Component Programming (without ATH)
- Immobilizer System Component Programming (with ATH)
- Key with Integrated Transmitter Programming
- Programming Additional Keys
- Replacing Keys
- Description and Operation
RENDER: 1.0x
NO RELATED
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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.