U1300 Class II Data Link Shorted To Ground

DTC U1300 Class II Data Link Shorted To Ground:

CIRCUIT DESCRIPTION
The Body Control Module (BCM) interfaces with other vehicles systems through the Class II serial data link.

CONDITIONS FOR SETTING THE DTC
The BCM detects a short to ground in the Class II serial data link.

ACTION TAKEN WHEN THE DTC SETS
The BCM stores DTC U1300 in memory.

CONDITIONS FOR CLEARING THE DTC
^ The BCM no longer detects a short to ground in the Class II serial data link.
^ The BCM monitors its own transmitted message on the Class II serial data link.
^ A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ Using a scan tool.

DIAGNOSTIC AIDS
^ DTC U1300 indicates that the Class II serial data link has been shorted to ground. The BCM sends DTC information to the Tech 2 scan tool via the Class II serial data link. If the Class II serial data link is currently shorted to ground, the Tech 2 scan tool will be unable to communicate with the BCM. Therefore. you will be unable to obtain a DTC U1300 as a current DTC. However, if the Tech 2 scan tool is able to communicate with the BCM and DTC U1300 is read, it will be a history DTC. Wiggle wires and connectors when performing circuit checks on the Class II serial data link. This can often cause the short to ground to appear.
^ The following conditions may cause an intermittent malfunction to occur:
- An intermittent short to ground in the Class II serial data link.
- The BCM is shorted to ground internally.
^ DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is in the RUN position with the BCM disconnected. When BCM diagnostics and repairs are completed refer to the Engine Controls for additional information on PCM related DTCs.

TEST DESCRIPTION
Number below refer to the step number on the diagnostic table.
3. Determines whether the malfunction is intermittent or the BCM is faulty.