DTC U1300: Class 2 Short To Ground: Testing
WARNING: This page is about a different car, the 1998 Cadillac Eldorado and 1998 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
DTC U1300 should always be a history code. If DTC U1300 is current, modules on class 2 serial data line cannot communicate with each other or diagnostic equipment. Check each module on class 2 serial data line for DTC U1300. If DTC U1300 is stored in a module, check for poor connections. If connections are okay, replace appropriate module. If DTC U1300 is stored in more than one module, check for intermittent short to ground in Purple wire between individual control modules. See WIRING DIAGRAMS .