Astro Van 2WD V6-4.3L VIN W (2001)
Information Bus: Symptom Related Diagnostic Procedures
Scan Tool Does Not Communicate With Class 2 Device
CIRCUIT DESCRIPTION
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information
and commands are exchanged among the modules. Connecting a scan tool to the DLC allows communication with the modules for diagnostic
purposes. DTCs may be set due to this symptom and during this diagnostic procedure. Complete the diagnostic procedure in order to ensure all the
DTCs are diagnosed and cleared from memory.
DIAGNOSTIC AIDS
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The BCM detects that the ignition is ON and sends the appropriate power mode message to the Other modules. Therefore, the BCM must be
connected to the DLC for any Other module to communicate with the scan tool.
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When the class 2 serial data circuit is shorted to battery negative voltage, U1300 will be set. Refer to DTC U1300. See: Testing and
Inspection/Diagnostic Trouble Code Tests and Associated Procedures/U Code Charts/U1300
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When the class 2 serial data circuit is shorted to battery positive voltage, U1301 will be set. Refer to DTC U1301. See: Testing and
Inspection/Diagnostic Trouble Code Tests and Associated Procedures/U Code Charts/U1301
TEST DESCRIPTION
Steps 1-2
