Scan Tool Does Not Communicate with High Speed GMLAN Device
Scan Tool Does Not Communicate with High Speed GMLAN Device
Modules connected to the GMLAN serial data circuit monitor for serial data communications on the GMLAN network during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module detects a bus-off condition a DTC U2100 will be set. This DTC can be retrieved as history only.
Diagnostic Aids
The engine will not start when there is a total malfunction of the GMLAN serial data circuits while the engine is not running. The following conditions may cause a total loss of GMLAN data communication:
* Any of the serial data circuits shorted to ground.
* Any of the serial data circuits shorted to voltage.
* A short between serial data circuits.
* An internal malfunction of a module on the GMLAN network that causes a short to voltage or ground.
Test
