Supplemental Inflatable Restraint (SIR)

Diagnostic Chart:

Circuit Schematic:

WARNING: During service procedures, be very careful when handling a sensing and diagnostic module (SDM). never strike or jar the SDM. Never power up the sir system when the SDM is not rigidly attached to the vehicle. All SDM and mounting bracket fasteners must be carefully torqued and the arrow must be pointing toward the front of the vehicle to ensure proper operation of the sir system. The SDM could be activated when powered while not rigidly attached to the vehicle which could cause deployment and result in personal injury.

NOTE: When DTC 25 has been set, it is necessary to replace the SDM. Setting DTC 25 will also cause DTC 71 to set. When a Saturn Portable Diagnostic (Scan) (PDT) Tool "Clear Codes" command is issued and the malfunction is still present, diagnostic trouble codes 25 and 71 will remain current. When a PDT "Clear Codes" command is issued and malfunction is no longer present DTC 25 will clear but DTC 71 will remain current. Ensure that the short to B+ condition is repaired prior to installing a replacement ADM to avoid damaging the ADM.


CIRCUIT DESCRIPTION
DTC 71 is an indication of a potential internal SDM malfunction and will set if any of the following conditions are detected:
1. 36 VLR (Voltage Loop Energy Reserve) voltage out of normal operating range.
2. Crash data recording reserved voltage discharge time failure for three consecutive ignition cycles.
3. The calculated checksum for internal memory does not match the stored value.
4. The voltage measured at "Driver Side Low" and/or "Passenger Side Low" is too high.
5. The sensing device inside the SDM which converts vehicle velocity changes to an electrical signal is malfunctioning.
6. The driver current source and/or passenger current source is malfunctioning.
7. The temporary memory storage area is malfunctioning.
8. SDM is unable to read from or write to EEPROM.
9. The arming sensor inside the SDM is not closed during a deployment event.
10. DTC 25 has been set.

DTC WILL SET WHEN:
Any of the indicated malfunctions are detected by the ADM. The malfunctions are tested at different times:
1. "Turn-On" and "Continuous Monitoring"
2. "Turn-On"
3. "Continuous Monitoring"
4. "Current Source Diagnostics"
5. Asynchronously

ACTION TAKEN:
SDM turns On the AIR BAG warning lamp and sets a diagnostic trouble code.

DTC WILL CLEAR WHEN:
A scan tool "Clear Codes" command is received by the ADM. Some of the indicated malfunctions will only allow the AIR BAG warning lamp to go out briefly then come back On.


DIAGNOSTIC AIDS
Was the "SIR Diagnostic System Check" performed?