Scan Tool Testing and Procedures

CIRCUIT DESCRIPTION
Modules connected to the Class II 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. Diagnostic trouble codes (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
^ When the Class II serial data circuit is shorted to ground, U1300 will be set. Refer to DTC U1300 Class 2 Data Link Low in [1][2]Data Link Communications. Data Link Connector
^ When the Class II serial data circuit is shorted to battery positive voltage U1301 will be set. Refer to DTC U1301 Class 2 Data Link High in Data Link Connector.