C 3500 HD Truck 2WD V8-8.1L VIN G (2002)
7. The module which was not communicating due to an open in the serial data circuit may have set Lost Communication DTCs for those modules that
it was monitoring.
Scan Tool Does Not Power Up
CIRCUIT DESCRIPTION
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:
^
Scan tool power battery positive voltage at terminal 16.
^
Scan tool power ground at terminal 4.
^
Common signal ground at terminal 5.
The scan tool will power up with the ignition off. Some modules however, will not communicate unless the ignition is on and the power mode master
(PMM) module sends the appropriate power mode message.
TEST DESCRIPTION
Steps 1-4
The number below refers to the step number on the diagnostic table.
4. If the battery positive voltage and ground circuits of the DLC are functioning properly. The malfunction must be due to the scan tool.