DTC U1301: Class 2 Data Link High: Description

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2002 GMC Savana, 2002 Chevrolet Chevy Express, 2001 GMC Savana Special, 2001 GMC Savana Camper Special, and 2001 GMC Savana. However, it is still accessible from the selected car via links, so may be relevant.

Modules connected to the class 2 serial data line monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged between modules. In addition, node alive (state of health) messages are transmitted by each module on the class 2 serial data line about once every 2 seconds.

When a module detects no messages and a high voltage on the class 2 serial data line for about 3 seconds, DTC U1301 is set, the setting of all other class 2 communication DTCs in inhibited and the module uses default values for all parameters received on the class 2 serial data line. DTC U1301 will set if no valid class 2 messages are detected on class 2 serial data circuit, voltage level detected on the class 2 serial data circuit is high. Conditions must be met for approximately three seconds. A current DTC U1301 will clear when a valid class 2 message is detected on serial data line or at the end of the current ignition cycle. A history DTC U1301 can only be cleared using scan tool.