B1155

Circuit Description
When the ignition switch is first turned to RUN, the body control module (SBM) sends a message over the serial data line Class 2 containing serial data keying information. When the ignition switch is first turned to RUN, the powertrain control module (PCM) sends a message over the serial data line Class 2 containing a partial vehicle identification number (VIN). The Inflatable Restraint Sensing and Diagnostic Module (SDM) receives these messages and compares the messages to the information stored in memory. For more detailed information about the data lines, refer to Data Link Communications Description.

Conditions for Setting the DTC
If either or both of the messages do not match information stored in the SDM, DTC B1155 will set, along with DTC B1159 and/or DTC B1160 depending on the message that does not match. If the SDM does not receive the serial data keying message from the SBM DTC B1159 will set without DTC B1155. If the SDM does not receive a partial VIN message from the PCM DTC B1160 will set without DTC B1155. The POWER-ON test inspects for these DTCs. The SBM and PCM send these messages only at POWER-ON.

Action Taken When the DTC Sets
The SDM commands the instrument cluster to turn ON the AIR BAG warning lamp and sets 1 or more diagnostic trouble codes.

Conditions for Clearing DTC B1155
The DTC will clear when 1 of the following conditions is met:
^ Current DTC.
The ignition switch is turned OFF.
^ History DTC.
- You issue a scan tool CLEAR CODES command.
- 250 malfunction free ignition cycles have occurred.

Conditions for Clearing DTC B1159 and B1160
The DTC will clear when 1 of the following conditions is met:
^ Current DTC
The SDM receives the correct message over the serial data line class 2. The SBM/PCM send this message only at POWER-ON.
^ History DTC
- You issue a scan tool CLEAR CODES command.
- 250 malfunction free ignition cycles have occurred.

Diagnostic Aids
DTC B1155 sets only when the wrong message is sent by the SBM or PCM. The State Of Health (SOH) DTCs may set in addition to DTC B1155, DTC B1159 and DTC B1160. SOH DTCs will likely clear when the malfunction causing DTC B1155, DTC B1159 and DTC B1160 in order to set is repaired. Refer to Diagnostic Aids for the specific SOH DTC.

Test Description
The numbers below refer to the step numbers on the diagnostic table:
2. If DTC B1155, DTC B1159, and DTC B1160 are all set, the SDM is receiving the massages from the SBM and the PCM, however both messages are incorrect according to the SDM in the vehicle.
4. If DTC B1155 and DTC B1159 are set, then the SDM is receiving the wrong message from the SBM.
6. If DTC B1155 and DTC B1160 are set, then the SDM is receiving the wrong message from the PCM.
8. If DTC B1159 is set alone, then the SDM did not receive the message from the SBM.
10. If DTC B1160 is set alone, then the SDM did not receive the message from the PCM.
12. If DTC B1160 and DTC Bi159 are set without DTC B1155, then the SDM did not receive either message from the SBM or the PCM.