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Home >> Cadillac >> 2012 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 871 (Data Communication System) >> Diagnostic Information and Procedures >> Scan Tool Does Not Communicate With Low Speed GMLAN Device >> Diagnostic Fault Information
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Diagnostic Fault Information

WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Scan Tool Does Not Communicate with Low Speed GMLAN Device

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Low Speed GMLAN Serial Data 1 21 1 -
Ground (DLC, Terminal 5) - 1 - -
1 An open between the data link connector (DLC) and C 203 will only effect the communication with the scan tool. The vehicle modules will still communicate.
  1. No communication on any low speed GMLAN module
  2. No communication on a specific low speed GMLAN module