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 instrument cluster flashes the AIR BAG warning lamp 7 times. If no SIR DTCs are present, the inflatable restraint sensing and diagnostic module (SDM) then commands the instrument cluster to turn the AIR BAG warning lamp OFF by sending a message over the serial data line class 2. The instrument cluster then returns a message to the SDM that the AIR BAG warning lamp is OFF. For more detailed information about the data lines, refer to Data Link Communications Description.

Conditions for Setting the DTC

If the SDM receives the wrong response from the instrument cluster after sending the AIR BAG warning lamp message 6 times, the SDM will set DTC B1163. A loss of State Of Health (SOH) DTC U1096 or DTC U1255 is also set. The test for DTC B1163 is run ASYNCHRONOUSLY during CONTINUOUS MONITORING.

Action Taken When the DTC Sets

The SDM sets DTC B1163 and either DTC U1096 or DTC U1255.

Conditions for Clearing the MIL/DTC

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

    • Current DTC
       - The ignition is turned OFF.
       - The SDM receives the correct instrument cluster message response 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

The following failures may cause a history DTC B1163 to set:

    • The instrument cluster lost B+ or ground while the ignition switch is in the RUN position
    • An intermittent short to B+ or ground in CKT 1807 serial data line class 2
    • An intermittent open in CKT 1807 serial data class 2

The State Of Health (SOH) DTCs will likely be set with DTC B1163 when communication is lost between the instrument cluster and the SDM. Verify that the instrument cluster is functioning properly. Use the SOH DTC diagnostic information in Data Link Connector - Cell 50.

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

  1. Malfunctions within the serial data line class 2 will set this DTC. These malfunctions are addressed in the SIR diagnostic system check. Failure in order to properly perform the SIR diagnostic system check may result in misdiagnosis.
  2. Turn the ignition switch to the RUN position.
  3. Clear the SIR DTCs.
  4. Request the SIR DTC display.

Is DTC B1163 set?

--

Go to Sensing and Diagnostic Module Integrity Check

Go to SIR Diagnostic System Check