For 1990-2009 cars

### Circuit Description

When the ignition is turned ON, the instrument panel cluster (IPC) flashes the AIR BAG indicator seven times. The inflatable restraint sensing and diagnostic module (SDM) performs diagnostic tests on the SIR system and then commands the IPC to turn the AIR BAG indicator OFF if no SIR malfunction exists. The AIR BAG indicator is controlled by the SDM via Class 2 serial data. If the Ignition 1 voltage is outside of the normal operating voltage range of 9-16 volts, the SDM will command the IPC to turn the AIR BAG indicator ON with no diagnostic trouble codes (DTCs) present.

### Diagnostic Aids

The IPC will turn the AIR BAG indicator ON if there is a loss of serial data communication between the IPC and the SDM. For more detailed information concerning the Class 2 data lines, refer to Data Link Communications Description and Operation in Data Link Communications.

The following are possible causes of the malfunction:

• | Ignition 1 voltage out of range

• | An internal IPC malfunction

• | An internal SDM malfunction

### Test Description

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

1. This step tests to see if the scan tool can communicate with the IPC.

2. This step tests to see if the Ignition 1 voltage is more than 9 V.

3. This step tests to see if the Ignition 1 voltage is more than 16 V.

4. This step tests to see if the SDM connector is damaged or corroded.

5. This step tests to see if there is an open or high resistance in the Ignition 1 voltage feed circuit to the SDM.

6. This step tests to see if there is an open or a high resistance in the Ignition 1 voltage feed circuit to the AIR BAG Fuse.

7. This step tests to see if there is an open or a high resistance in the SDM ground circuit.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Connector End View Reference: SIR Connector End Views
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 the ignition ON.

Does the AIR BAG indicator flash seven times?

--

Go to Step 4

Go to Step 3

3 | Replace the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gages and Console. Did you complete the replacement? | -- | Go to Step 13 | --
4 | Note the AIR BAG indicator after it has flashed seven times. Does the AIR BAG indicator turn OFF after flashing seven times? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 5
5 |

1. Install a scan tool.
2. Attempt to communicate with the IPC.

Does the scan tool communicate with the IPC?

--

Go to Step 6

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

6 | 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 7 | Go to Step 8
7 | 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 12
8 |

1. Turn OFF the ignition.
2. Disconnect the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
3. Inspect the SDM connector for damage or corrosion that may cause the malfunction. 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 13

Go to Step 9

9 |

1. Remove the AIR BAG Fuse.
2. Test the Ignition 1 voltage feed circuit to the SDM for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 10

10 | Test the Ignition 1 voltage feed circuit to the AIR BAG Fuse for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11
11 |

1. Turn OFF the ignition.
2. Test the SDM ground circuit for an open or a high resistance.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

12 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | --
13 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2