B1153

CAUTION: Be careful when you handle a Sensing & Diagnostic Module (SDM). Do not strike or jolt the SDM. Before applying power to the SDM:
^ Remove any dirt, grease, etc. from the mounting surface.
^ Position the SDM horizontally on the mounting surface.
^ Point the arrow on the SDM toward the front of the vehicle.
^ Tighten all of the SDM fasteners and SDM bracket fasteners to the specified torque value.
Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.

CIRCUIT DESCRIPTION
The inflatable restraint Sensing and Diagnostic Module (SDM) contains a sensing device which converts vehicle longitudinal velocity changes to an electrical signal. The electrical signal generated is processed by the SDM and then compared to a value stored in memory. When the generated signal exceeds the stored value, additional signal processing is performed and the generated signals are compared to signals stored in memory. When two of the generated signals exceed the stored values, the SDM will cause current to flow through the frontal inflator modules, deploying the frontal air bags. DTC B1153 will set with DTC B1151 when a deployment occurs while a frontal inflator circuit fault is present that could possibly result in a non-deployment situation in one or both frontal inflator modules. A side air bag deployment will NOT set a DTC B1151/53.

CONDITION FOR SETTING THE DTC
The SDM detects a frontal crash, up to 30 degrees off the longitudinal centerline of the vehicle, of sufficient force to warrant deployment of the frontal air bags and an inflator circuit fault is present.

ACTION TAKEN WHEN THE DTC SETS
The SDM does the following:
^ Commands the Instrument Panel Cluster (IPC) to turn ON the AIR BAG warning lamp.
^ Records Crash Data.
^ Sets a diagnostic trouble code.
^ Sends a message over the Serial Data Line Class 2.

CONDITIONS FOR CLEARING THE DTC
A scan tool Clear DTCs command is received by the SDM.

DIAGNOSTIC AIDS
DTC B1153 will be accompanied by another DTC(s) (other than DTC B1151). Repair the malfunction causing the other DTC(s) (other than DTC B1171) before you replace the SDM.

DTC TABLE TEST DESCRIPTION
Numbers below refer to step numbers on the diagnostic table.
2. If the frontal inflator modules have not deployed, DTC B1151/53 may have set falsely.
3. If DTC B1151/53 has set with no signs of frontal impact, the diagnostic trouble code has set falsely.