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 MANUALSCHEVROLET2006SUBURBAN K2500, 6.0 UREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1266 (DATA COMMUNICATION SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESSCAN TOOL DOES NOT COMMUNICATE WITH LOW SPEED GMLAN DEVICECIRCUIT/SYSTEM TESTING
2006 Chevrolet Suburban K2500, 6.0 U
Circuit/System Testing
2006 Chevrolet Suburban K2500, 6.0 USECTION Circuit/System Testing
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
- Test for less than 1.0 ohm between the ground circuit terminal 5 of the DLC and ground.
- If greater than the specified range, test the ground circuit for open/high resistance.
- Ignition OFF, disconnect the harness connector at JX 205.
- Ignition ON, test for less than 1 volt between the serial data circuit terminal 1 of the DLC and ground.
- If greater than the specified range, test the serial data circuit for a short to voltage.
- Test for infinite resistance between the serial data circuit terminal 1 of the DLC and ground.
- If less than the specified value, test the serial data circuit for a short to ground.
- Test for less than 2 ohms on the serial data circuit between terminal 1 of the DLC and terminal 1 of JX 205.
- If greater that the specified range, test the serial data circuit for an open/high resistance.
- Install a 3-amp fused jumper wire between terminal 1 and terminal 2 of JX 205. Attempt to communicate with the remote control door lock receiver (RCDLR). Communication should be available.
- If communication is not available refer to JX 405 Circuit Test .
- Install another 3-amp fused jumper wire to terminal 1 of JX 205.
- With RCDLR communications established, use the other end of the jumper wire to connect all other terminals of JX 205, harness side, one at a time and verify that low speed communication remains available to the RCDLR.
- If communication is interrupted after connecting an individual module at JX 205, test the serial data circuit between JX 205 and the last module connected for a short to voltage or short to ground. If the circuit tests normal, replace the module that caused no communication.
IMPORTANT:
Allow communications for 5 seconds after connecting a module with the jumper to determine if communication is interrupted or not.
RENDER: 1.0x
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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.