Cobalt L4-2.4L VIN B (2006)
Information Bus: Testing and Inspection
Scan Tool Does Not Communicate with Low Speed GMLAN Device
SCAN TOOL DOES NOT COMMUNICATE WITH LOW SPEED GMLAN DEVICE
Modules connected to the low speed GMLAN serial data circuits monitor for serial data communications on the low speed GMLAN network during
normal vehicle operation. Operating information and commands are exchanged among the modules. When a module detects a bus-off condition, DTC
U2100 will be set. These DTCs can be retrieved as history only.
Diagnostic Aids
The engine will not start when there is a total malfunction of the low speed GMLAN serial data circuits while the engine is not running. The following
conditions may cause a total loss of low speed GMLAN data communication:
-
Any of the low speed GMLAN serial data circuits shorted to ground or voltage
-
A module internal malfunction that causes a short to voltage or ground on the low speed GMLAN circuits
Test Description