For 1990-2009 cars

### Circuit Description

When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) flashes the AIR BAG indicator seven times. The SDM performs diagnostic tests on the SIR system and then turns the AIR BAG indicator OFF if no SIR malfunctions exists. If the ignition 1 voltage is outside of the normal operating range (9-16 volts), the SDM will turn the AIR BAG indicator ON with no DTCs present.

### Diagnostic Aids

The AIR BAG indicator will turn ON if the SDM connector is damaged or not properly connected to the SDM. The AIR BAG indicator will also turn ON if the shorting bar that is located within the SDM connector is damaged. In order to disable the shorting bar from the AIR BAG indicator control circuit and the SDM ground circuit within the SDM connector, the following conditions must be met:

• | The SDM connector must be properly connected to the SDM.

• | The connector position assurance (CPA) must be properly installed to the SDM connector.

### Test Description

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

1. Tests to see if there is sufficient voltage to the SDM.

2. Tests to see if there is excessive voltage to the SDM.

3. Tests to see if the SDM connector and shorting bars are damaged or corroded.

4. Tests to see if the SDM terminals or lifting tabs are damaged or corroded.

5. Tests to see if the IPC connector or terminals are damaged or corroded.

6. Tests the AIR BAG indicator control circuit for a short to ground.

7. Tests to see if the SDM connector and shorting bars are damaged or corroded.

8. Tests to see if the SDM terminals or lifting tabs are damaged or corroded.

9. Tests the ignition feed circuit for an open or a high resistance.

10. Tests the SDM ground circuit for an open or a high resistance.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: SIR Schematics
1 | Did you perform the Diagnostic System Check - SIR? | -- | Go to Step 2 | Go to Diagnostic System Check - SIR
2 |

1. Turn OFF the ignition.
2. Note the AIR BAG indicator while turning ON the ignition.

Does the AIR BAG indicator remain ON at all times?

--

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3 |

1. Install a scan tool.
2. With a scan tool, observe the SIR data list display.

Does the scan tool indicate that the ignition voltage is greater than the specified value?

9 V

Go to Step 4

Go to Step 9

4 | Does the scan tool indicate that the ignition voltage is greater than the specified value? | 16 V | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | Go to Step 5
5 |

1. Turn OFF the ignition.
2. Disconnect the SDM connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
3. Inspect the SDM connector and all shorting bars for damage or corrosion. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 6

6 | Inspect the SDM terminals and the shorting bar lifting tabs for damage or corrosion. Does the SDM terminals or the shorting bar lifting tabs exhibit any signs of damage or corrosion? | -- | Go to Step 13 | Go to Step 7
7 |

1. Disconnect the instrument panel cluster (IPC) connector. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.
2. Inspect the IPC connector and the IPC terminals for damage or corrosion. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 8

8 |

1. Install the J 42113 SIR Shorting Bar Tool into the SDM connector above the AIR BAG indicator control circuit and the SDM ground circuit.
2. Test the AIR BAG indicator control circuit for a short to ground.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 13

9 |

1. Turn OFF the ignition.
2. Disconnect the SDM connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
3. Inspect the SDM connector and all shorting bars for damage or corrosion. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

10 | Inspect the SDM terminals and the shorting bar lifting tabs for damage or corrosion. Does the SDM terminals or the shorting bar lifting tabs exhibit any signs of damage or corrosion? | -- | Go to Step 13 | Go to Step 11
11 |

1. Disconnect the ignition switch connector. Refer to Ignition Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt.
2. Test the ignition feed circuit for an open or a high resistance.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 12

12 | Test the SDM ground circuit for an open or a high resistance. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13
13 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | Go to Step 14 | --
14 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 3