GM Service Manual Online
For 1990-2009 cars only

Object Number: 397192  Size: MF
SIR Components
SIR System Operation
SIR Handling Caution
Handling ESD Sensitive Parts Notice

Circuit Description

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 identification information. The message contains a partial vehicle identification number (VIN). The inflatable restraint sensing and diagnostic module (SDM) receives this message and compares the message to the information stored in memory. For more detailed information about the data lines, refer to Data Link Connector-Cell 50. DTC B1160 is diagnosed in the DTC B1155 Table.

Conditions for Setting the DTC

If the SDM does not receive the partial VIN message from the PCM, DTC B1160 will set without DTC B1155. If the message from the PCM does not match the information stored in the SDM, DTC B1155 will set, along with DTC B1160. The POWER-ON test inspects for these DTCs. The PCM only sends this message 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 the MIL/DTC

The DTC will clear when one of the following conditions is met:

    • Current DTC
        The SDM receives the correct message over the serial data line class 2.
    • History DTC
       - You issue a scan tool CLEAR CODES command.
       - 250 malfunction free ignition cycles have occurred.

Diagnostic Aids

DTC B1160 will set without DTC B1155 when the PCM is inoperative. DTC B1155 sets only when the wrong message is sent by the PCM . State Of Health (SOH) DTCs may set in addition to DTC B1160. SOH DTCs will likely clear when the malfunction causing DTC B1160 to set is repaired. DTC B1160 is diagnosed in the DTC B1155 Table.

Step

Action

Value(s)

Yes

No

1

Was the SIR Diagnostic System Check performed?

--

Go to Step 2

Go to SIR Diagnostic System Check

2

This DTC is diagnosed in the DTC B1155 table.

Was the DTC B1155 table followed?

--

Go to Sensing and Diagnostic Module Integrity Check

Go to DTC B1155 SDM Calibration Mismatch