For 1990-2009 cars

### Circuit Description

IGNITION 1 voltage is applied to terminal 8. When the inflatable restraint Sensing and Diagnostic Module (SDM) recognizes that IGNITION 1 voltage is greater than 8.2 volts, then the SDM flashes the AIR BAG warning lamp seven times in order to verify the operation. At this time the SDM performs the Power-On tests followed by the Resistance Measurement test and the Continuous Monitoring tests. Upon detection of a malfunction, the SDM sets a current diagnostic trouble code and the SDM illuminates the AIR BAG warning lamp. The SDM will clear the current diagnostic trouble codes, and the SDM will move these trouble codes to a history file under the following conditions:

• | The malfunction is no longer detected

• | The ignition switch is cycled

This does not include DTC B1019, DTC B1025, DTC B1051, and DTC B1053 which are latched codes. You cannot clear a latched code. Additionally DTC B1071 may not clear after you issue a CLEAR CODES command. Repair the malfunction that set the DTC before you replace the SDM.

This table assumes that you have performed the SIR Diagnostic System Check and either a symptom table or a diagnostic trouble code table diagnosis. When all circuitry outside the inflatable restraint Sensing and Diagnostic Module (SDM) operates properly, as indicated by the appropriate diagnostic table, and the symptom or DTC remains unchanged, perform the following diagnostic procedures in order to verify the need for SDM replacement.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This test confirms a current malfunction. If no current malfunction is occurring (History DTC set), reference the Diagnostic Aids for the appropriate diagnostic trouble code. Do not replace the SDM for a history DTC.

2. This test checks for a malfunction introduced into the SIR system during the diagnostic process. It is extremely unlikely that a malfunctioning SDM would cause a new malfunction to occur during the diagnostic process.

3. The SDM should be replaced only when all the circuitry outside the SDM is found to operate properly, as indicated by the appropriate diagnostic table.

This table assumes that you have performed the SIR Diagnostic System Check and either a symptom table or a diagnostic trouble code table diagnosis. When all circuitry outside the inflatable restraint Sensing and Diagnostic Module (SDM) operates properly, as indicated by the appropriate diagnostic table, and the symptom or DTC remains unchanged, perform the following diagnostic procedures in order to verify the need for SDM replacement.

#### Integrity Check

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Were you sent here from a Symptom Table or a Diagnostic Trouble Code Table? | -- | Go to Step 2 | Go to SIR Diagnostic System Check
2 |

1. Turn the ignition switch to the LOCK position.
2. Reconnect all the SIR system components. Ensure all the components are properly mounted.
3. Make sure the ignition switch has been in the OFF position for at least 30 seconds.
4. Observe the AIR BAG warning lamp while turning the ignition switch to the ON position.

Does the AIR BAG warning lamp flash seven times then turn OFF?

--

Go to Step 7

Go to Step 3

3 | Using the scan tool, request the SIR diagnostic trouble code display. Is the same symptom or DTC occurring as when the SIR Diagnostic Symptom Check was first performed? | -- | Go to Step 4 | Go to the indicated table
4 |

1. Clear the SIR diagnostic trouble codes.
2. Turn the ignition switch to the LOCK position for at least 30 seconds.
3. Observe the AIR BAG warning lamp while turning the ignition switch to the ON position.

Does the AIR BAG warning lamp flash seven times then turn OFF?

--

System OK

Go to Step 5

5 |

1. Turn the ignition switch to the LOCK position.
2. Replace the inflatable restraint Sensing and Diagnostic Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement in this section.

Did you replace the SDM?

--

Go to Step 6

--

6 |

1. Reconnect all the SIR system components.
2. Confirm that all the components are properly mounted.

Are all SIR components been connected and properly mounted?

--

Go to SIR Diagnostic System Check

--

7 |

1. The symptom or DTC is no longer occurring.
2. Clear the SIR diagnostic trouble codes.

Did you clear the SIR diagnostic trouble codes?

--

Go to SIR Diagnostic System Check

--