Sierra 1500 4WD V8-6.0L (2007)
The data link connector (DLC) is a standardized 16-cavity connector. The DLC low speed serial data circuit is connected directly to the instrument panel
(I/P) splice then to all other splices or modules. Connector design and location is dictated by an industry wide standard, and is required to provide the
following:
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Pin 1 GMLAN low speed communications terminal
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Pin 4 scan tool power ground terminal
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Pin 5 common signal ground terminal
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Pin 6 high speed GMLAN serial data bus (+) terminal
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Pin 14 high speed GMLAN serial data bus (-) terminal
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Pin 16 scan tool power, battery positive voltage terminal
Serial Data Reference
The scan tool communicates over the various busses on the vehicle. When a scan tool is installed on a vehicle, the scan tool will try to communicate with
every module that could be optioned into the vehicle. If an option is not installed on the vehicle, the scan tool will display No COMM for that options
specific control module.
In order to avert misdiagnoses of No Communication with a specific module, refer to Data Link References for a list of modules, the busses they
communicate with, and the RPO codes for a specific module. See: Data Link Connector/Testing and Inspection
