Envoy 4WD V8-5.3L (2007)
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The transmission control module (TCM)
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The ECM
The interaction between high speed GMLAN and class 2 is assured by ECM, which acts as a gateway between the links.
GMC Workshop Service and Repair Manuals
Information Bus|Testing and Inspection >
< Technician Safety Information|Page 7595
Page 2
