U1255 Serial Data Line Class 2 Initialization Error - SRS

CIRCUIT DESCRIPTION
While the ignition switch is in the RUN position, The inflatable restraint Sensing and Diagnostic Module (SDM) sends messages to other module communicating on the Serial Data Line Class 2. For more detailed information about the data lines, refer to Computer System Diagnosis.

CONDITIONS FOR SETTING THE DTC
The SDM requests information from another module and does not receive a response after 6 tries.

ACTION TAKEN WHEN THE DTC SETS
The SDM sets (a) diagnostic trouble code. The SDM does NOT turn on the AIR BAG warning lamp.

CONDITIONS FOR CLEARING THE DTC
Current DTC One of the following must occur to clear the DTC:
- The ignition switch is turned OFF.
- The SDM receives the message response over Serial Data Line Class 2.
^ History DTC.
- You issue a scan tool CLEAR CODES command.
- 250 malfunction-free ignition cycles have occurred.

DIAGNOSTIC AIDS
If DTC U1255 is set, clear DTCs and cycle the ignition. If DTC U1255 is still current, ensure all of the modules are functioning properly and the Serial Data Line Class 2 is not shorted to ground or shorted to voltage. It is highly unlikely that the inflatable restraint Sensing and Diagnostic Module (SDM) will set a State Of Health (SOH) message if the SDM is faulty. Other State Of Health (SOH) DTCs may set in addition to DTC U1255. Refer to Diagnostic Aids for that specific SOH DTC.