GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1998 🢒 Park Avenue 🢒 Body and Accessories 🢒 Wiring Systems 🢒 SIR Diagnostic System Check

Caution: In order to avoid deploying the air bag when troubleshooting the SIR system, use only the equipment specified in this manual and the instructions given in this manual. Failure to use the specified equipment as instructed could cause air bag deployment, personal injury to you or someone else, or unnecessary SIR system repairs.

These diagnostic procedures will help you to find and repair SIR system malfunctions. This service category also contains information for repairing SIR system malfunctions. For best results, use the diagnostic tables, and follow the sequence listed below:

  1. Perform the SIR Diagnostic System Check. All SIR diagnostics must begin with the SIR Diagnostic System Check. The SIR Diagnostic System Check determines the following:
    2. • Proper AIR BAG warning lamp operation
    • Ability of the SDM to communicate through the Data Link Connector (DLC)
    • Existence of SIR Diagnostic Trouble Codes (DTC)
    • Existence of State Of Health (SOH) Diagnostic Trouble Codes (DTC)
  2. Refer to the diagnostic table as directed by the SIR Diagnostic System Check. The diagnostic tables will help enable you to diagnose any SIR system malfunction. Bypassing these procedures may result in the following:
    3. • Extended Diagnostic Time
    • Incorrect Diagnosis
    • Incorrect Parts Replacement
  3. Repeat the SIR Diagnostic System Check after you perform any repair or diagnostic procedures. This will verify that you correctly performed the repair. This will also ensure that no other malfunctions exist.

Circuit Description

The ignition switch supplies Ignition 1 voltage to the inflatable restraint Sensing and Diagnostic Module (SDM) at terminal 3 using the SDM Fuse. The ignition switch also supplies Ignition 1 voltage to the Instrument Panel Cluster (IPC). When the ignition switch is first turned to the RUN position, the IPC responds by flashing the AIR BAG warning lamp seven 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. If the IPC receives no message from the SDM, the IPC will turn the warning lamp ON.

Diagnostic Aids

You must diagnose the diagnostic trouble codes in the order specified by the SIR Diagnostic System Check. Failure to do so may result in the following:

    • Extended Diagnostic Time
    • Incorrect Diagnosis
    • Incorrect Parts Replacement

If the AIR BAG warning lamp does not flash seven times when the ignition switch is turned to RUN, then the IPC is not operating correctly.

If a State Of Health (SOH) DTC is present, refer to the Diagnostic Aids for that specific SOH DTC in this section.

Test Description

Refer to step numbers on the diagnostic table.

  1. The Instrument Panel Cluster (IPC) should flash the AIR BAG warning lamp seven times after the ignition switch is first turned to the RUN position.

    2.

  2. The AIR BAG warning lamp should turn OFF after flashing seven times.

    3.

  3. This test checks for the proper operation of the Serial Data line.

    4.

  4. This test will identify the stored diagnostic trouble codes and whether they are current or history.

    5.

  5. This test checks for the proper operation of the Serial Data line. This test also identifies any stored history diagnostic trouble codes.

SIR Diagnostic System Check

Step

Action

Value(s)

Yes

No

1

Note the AIR BAG warning lamp while turning the ignition switch to the RUN position.

Does the AIR BAG warning lamp flash seven times?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster Instrument Panel, Cluster, and Gauges

2

Note the AIR BAG warning lamp after it flashed seven times.

Does the AIR BAG warning lamp go OFF and stay OFF for 30 seconds?

--

Go to Step 5

Go to Step 3

3
  1. Turn the ignition switch to the OFF position.
  2. Connect a scan tool to the Data Link Connector. Follow the directions in the instruction manual of the scan tool.
  3. Turn the ignition switch to the RUN position.
  4. Request the SIR Diagnostic Trouble Code (DTC) display.

Is a current DTC displayed?

--

Go to Step 4

Go to Lamp Flashes Seven Times, Stays On, No DTCs Set

4
  1. Turn the ignition switch to the OFF position.
  2. Record the displayed DTCs on the repair order, specifying as current or history.
    3. • When DTC B1125 is set, go to DTC B1125 Driver/Pass Deploy Loop Short to Voltage .
    • When DTC B1151 is set, go to DTC B1151 Deployment Commanded - Frontal .
  3. Diagnose the remaining DTCs from lowest to highest.
  4. When only history DTCs exist, refer to Diagnostic Aids for that specific DTC. A history DTC indicates the malfunction has been repaired or is intermittent.

Has current DTC diagnosis been performed and the current DTCs cleared?

--

Go to Step 1

--

5
  1. Turn the ignition switch to the OFF position.
  2. Connect a scan tool to the Data Link Connector. Follow the directions in the instruction manual of the scan tool.
  3. Turn the ignition switch to the RUN position.
  4. Request the SIR Diagnostic Trouble Code (DTC) display.

Is a history DTC displayed?

--

Go to Step 7

Go to Step 6

6

Does the scan tool indicate no data received?

--

Go to Diagnostic System Check - Data Link Communications in Wiring Systems

System OK

7
  1. Turn the ignition switch to the OFF position.
  2. Record the displayed DTCs on the repair order specifying as history.
  3. When DTC B1125 is set, go to DTC B1125 Driver/Pass Deploy Loop Short to Voltage .
  4. When DTC B1152 is set, go to DTC B1152 Data Area Full .
  5. When DTC B1171 is set, go to DTC B1171 Internal SDM Failure .
  6. For all other DTCs, Refer to Diagnostic Aids for that specific DTC. A history DTC indicates the malfunction has been repaired or is intermittent. Refer to Body Control System to diagnose State Of Health (SOH) DTCs after diagnosing SIR DTCs.

Has all diagnosis been performed and all the SIR and SOH DTCs cleared?

--

Go to Step 1

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