Troubleshooting Hints

Note: Perform before beginning system diagnosis.

1. First step of Class 2 serial data line should be to check for loss of state of health Diagnostic Trouble Code (DTC)s using a scan tool.

2. DTC U1300 sets if the Class 2 serial data line experiences short to ground. However, this code will never be received as current because the Class 2 bus does not function during this condition.

3. DTC U1301 sets if the Class 2 serial data line experiences short to B+. However, this code will never be received as current because the Class 2 bus does not function during this condition.

4. The Class 2 serial data line does not have a "master." controller. Communication occurs by peer-to-peer transfers. Therefore, an open circuit on one part of the Class 2 circuit typically does not cause a total loss of communication of all modules on the bus.