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 MANUALSCHEVROLET2002AVALANCHE 2500, RWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 971 (DATA LINK COMMUNICATION SYSTEM)
2002 Chevrolet Avalanche 2500, RWD
Section 971 (Data Link Communication System)
2002 Chevrolet Avalanche 2500, RWDSECTION Section 971 (Data Link Communication System)
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
- Specifications
- Schematic and Routing Diagrams
- Component Locator
- Diagnostic Information and Procedures
- Diagnostic Starting Point - Data Link Communications
- Diagnostic Trouble Code (DTC) List
- DTC U0001: High Speed CAN Communication Bus
- DTC U0100 To U0299: GMLAN High Speed Serial Data Missing
- DTC U1000 and U1255: Class 2 Data Link Malfunction/Lost Communications
- DTC U1001 To U1254: Module U1XXX Communication
- DTC U1300, U1301, or U1305: Class 2 Data Link
- DTC U2105: Lost Communications with Engine Control System
- Scan Tool Does Not Power Up
- Scan Tool Does Not Communicate with Class 2 Device
- Scan Tool Does Not Communicate with High Speed GMLAN Device
- Data Link References
- Repair Instructions
- Description and Operation
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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.