B1159

CIRCUIT DESCRIPTION
When the ignition is turned to RUN, the Instrument Panel Cluster (IPC) sends two messages over the Serial Data Line Class 2 containing identification information. The first message contains serial data keying information. The second message contains a partial Vehicle Identification Number (VIN). The inflatable restraint Sensing and Diagnostic Module (SDM) receives these messages and compares them to information stored in memory. These messages are sent once per ignition cycle at Power-ON. For more detailed information about the data lines, refer to Computer System Diagnosis.

CONDITIONS FOR SETTING THE DTC
If either or both of the messages from the Instrument Panel Cluster (IPC) do(es) 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 IPC, DTC B1159 will set without DTC B1155. If the SDM does not receive a partial VIN message from the IPC, DTC B1160 will set without DTC B1155. The POWER-ON test checks for these DTCs. The IPC sends these messages only at IPC Power-ON.

ACTION TAKEN WHEN THE DTC SETS
The SDM commands the IPC to turn ON the AIR BAG warning lamp and sets (a) diagnostic trouble code(s).
^ History DTC.
- You issue a scan tool CLEAR CODES command.
- 250 malfunction-free ignition cycles have occurred.

CONDITIONS FOR CLEARING DTC B1159 and B1160
^ Current DTC.
- The SDM receives the correct message over the Serial Data Line Class 2. The IPC sends this message only at IPC 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 IPC. State Of Health (SOH) DTCs may set in addition to DTC B1155/59/60. SOH DTCs will likely clear when the malfunction causing DTC B1155/59/60 to set is repaired. Refer to Diagnostic Aids for that specific SOH DTC.