LaCrosse FWD V6-3.0L (2010)
the systems functionality is required. Once the CGI network is awake, all message transfers on the CGI are initiated by the Radio. Slave devices such as
the Info Display Module and Radio/HVAC Control may not transmit unless they are responding to a request from the Radio.
Dual wire CGI networks have a termination resistance between the CGI+ (CAN- High) and CGI- (CAN- Low) conductors at each end of the bus. Each
termination resistance is 120 ohms.
The communication function of the CGI shall be enabled or disabled based on the voltage level of a dedicated input (typically called "Center Stack
Wake"). The network will stay awake as long as this discrete signal is driven low to less than 1.5 V. When the Radio determines that the communication
bus needs to be operational or active, it shall generate the wake-up signal by pulling this signal circuit low.
The Radio can execute a warm reset of the Info Display Module if the Info Display Module fails to respond to Radio's request via the CGI interface.
Center Stack Reset is a low-asserted pull down output (less than 1.5 V) from the Radio to the Info Display Module and has the same electrical
characteristics as those for the Center Stack Wake signal defined above.
Data Link Connector (DLC)
The data link connector (DLC) is a standardized 16-cavity connector. Connector design and location is dictated by an industry wide standard, and is
required to provide the following:
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Pin 1 Low speed GMLAN communications terminal
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Pin 3 Mid speed GMLAN serial bus (+) 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 11 Mid speed GMLAN serial bus (-) terminal
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Pin 12 Chassis high speed GMLAN serial bus terminal
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Pin 13 Chassis high speed GMLAN serial 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 buses 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
control module. In order to avert misdiagnoses of No Communication with a specific module, refer to Data Link References (See: Testing and
Inspection/Initial Inspection and Diagnostic Overview) for a list of modules, the buses they communicate with, and the RPO codes for a specific module.
