Diagnostic Aids
WARNING: This page is about a different car, the 2005 Saturn L300. However, it is still accessible from the selected car via links, so may be relevant.
The following conditions will cause a class 2 serial data communication malfunction:
- The body control module (BCM) detects that the ignition switch is ON and sends the appropriate power mode message to the other modules connected to the class 2 serial data circuit. The BCM must be connected to the class 2 serial data circuit for many other modules to communicate with the scan tool.
- A class 2 serial data circuit shorted to ground-A history U1300 will set in all modules. Refer to DTC U1300, U1301, or U1305 .
- A class 2 serial data circuit shorted to voltage-A history U1301 will set in all modules. Refer to DTC U1300, U1301, or U1305 .
- A class 2 serial data circuit shorted to ground or voltage-A history U1305 will set in all modules. Refer to DTC U1300, U1301, or U1305 .
- An internal condition within a module or connector on the class 2 serial data circuit, that causes a short to voltage or ground to the class 2 serial data circuit
- If the malfunction is intermittent, check for poor connections at the suspect module. Wiggling the harness wiring may help in locating the fault.