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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Data Link Communications System >> Diagnostic Information and Procedures >> DTC U1300, U1301, or U1305: No Valid Messages Are Detected On The Class 2 Serial Data Circuit >> Circuit Description

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. In addition to this, Node Alive messages are transmitted by each module on the class 2 serial data circuit about once every 2 seconds. When the module detects one of the following conditions on the class 2 serial data circuit for approximately 3 seconds, the setting of all other class 2 serial communication DTCs is inhibited and a DTC will set.

Fig 1: DTC U1300, U1301, or U1305 Condition Chart
G01566029Courtesy of GENERAL MOTORS CORP.