Circuit Description
When the ignition switch is first turned to RUN, the SIR fuse applies battery voltage to the inflatable restraint sensing and diagnostic module (SDM) at the ignition positive voltage input, terminal 3. The battery voltage is applied to the instrument panel cluster (IPC). The IPC responds by flashing the AIR BAG warning lamp 7 times. The SDM performs tests on the SIR system while the IPC is flashing the warning lamp. If the SDM detects no malfunctions, the SDM commands the IPC to turn the warning lamp OFF. If the SDM detects a malfunction, the SDM commands the IPC to turn the warning lamp ON. The SDM commands the IPC over the serial data line class 2.
Diagnostic Aids
If the IPC receives no message from the SDM the IPC will do the following when the ignition is turned to RUN:
| • | Flash the AIR BAG warning lamp 7 times |
| • | Turn the warning lamp ON |
| • | Set the DTC U1255 (Class 2 initialization error-IPC) |
| • | If the ignition is in the RUN position, has received at least one message from the SDM, and the IPC loses communication with the SDM, the IPC will set DTC U1088 and the SDM will set DTC U1096. |
When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616 Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections . When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair .
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: AIR BAG Warning Indicator flashes seven times, stays on, with no DTCs set. | ||||
1 | Was the SIR Diagnostic System Check performed? | -- | ||
2 |
Will scan tool command the AIR BAG Warning Indicator ON then OFF? | -- | ||
3 | Replace the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Have the repairs been completed? | -- | -- | |
4 | Suspect the instrument panel cluster (IPC). Refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges, and Console. Have the repairs been completed? | -- | -- | |
