DTC U1255: Loss Of Class 2 Serial Data Fault (General): Description
WARNING: This page is about a different car, the 1999 Buick Regal and 1999 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
When ignition switch is turned to RUN position, Body Control Module (BCM) receives a vehicle security powertrain status message from Powertrain Control Module (PCM). DTC U1255 will set when BCM does not receive this message within one minute of ignition switch being turned to RUN position. BCM will send message to IPC to come on SECURITY indicator warning light. A current DTC U1255 will change to a history code when BCM receives vehicle security powertrain status message from PCM. If conditions for malfunction no longer exist, history DTC will clear after 100 consecutive ignition cycles. DTC U1255 will also clear when scan tool is used to clear codes.
NOTE:
When ignition switch is turned to RUN position with BCM disconnected, PCM-related DTC P1626 will be set. After BCM repair is completed, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.