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Home >> Pontiac >> 2001 >> Aztek Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 894 (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
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Circuit Description

WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.

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
G01476057Courtesy of GENERAL MOTORS CORP.