U1255 Class 2 Initialization Error - DLC

DTC U1255: Class 2 Initialization Error:

CIRCUIT DESCRIPTION
While the Ignition Switch is in RUN, modules communicating on the Class 2 Data Bus send a "State of Health" (SOH) message every 5 seconds to ensure that the system is operating properly.

CONDITIONS FOR SETTING THE DTC
^ This Diagnostic Trouble Codes (DTCs) will set only if DTC B1982, B1983, U1300 or U1301 is not current.
^ The module requests a message for initialization and the following set of criteria is met:
- The request is not acknowledged after all message retries are sent out.
- The requested information has an internal failsoft value.
- The source ID with the desired information is not known.

CONDITIONS FOR CLEARING THE DTC
^ The conditions for setting the DTC are no longer met.
^ The DTC clears on every Power Mode Initialization.

DIAGNOSTIC AIDS
^ This serial data DTC does not normally represent a failure within the module. This is not true when there is an intermittent connection of the Class 2 data line(s) to the module. When serial data codes are history, know all possible serial data DTCs and which ones are set in each module, before diagnosing the Class 2 concern.
^ If DTC U1255 is set, clear DTCs and cycle ignition. If DTC U1255 is still current, ensure that all modules are functioning properly and the Class 2 Data Bus is not shorted to ground or voltage.