For 1990-2009 cars

### Circuit Description

The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device (accelerometer) that converts vehicle velocity changes to an electrical signal. The SDM compares this electrical signal to a value stored in memory. When the generated signal exceeds the stored value, the SDM performs additional signal processing and compares the generated signals to values stored in memory. When two of the generated signals exceed the stored values, the SDM will cause current to flow through the inflator modules, deploying the air bags and causing DTC B1051 to set.

### Conditions for Setting the DTC

The SDM detects a frontal crash, up to 30 degrees off the centerline of the vehicle, of sufficient force to warrant deployment of the frontal air bags.

### Action Taken When the DTC Sets

• | The SDM sets a DTC B1051.

• | The SDM turns ON the AIR BAG warning indicator.

• | The SDM records crash data.

### Conditions for Clearing the DTC

DTC B1051 is a latched code. You cannot permanently clear a latched code. Replace the SDM after following the instructions in the diagnostic table.

### Test Description

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

1. If the inflator module(s) has not deployed, DTC B1051 may have set falsely.

2. If DTC B1051 has set with no signs of frontal impact, the DTC may have set falsely.

#### DTC B0051 Deployment Commanded

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 | Turn the ignition switch to the OFF position. Has the inflator module(s) deployed? | -- | Go to Step 5 | Go to Step 3
3 | Inspect the front of the vehicle and the undercarriage for signs of impact. Are there signs of impact? | -- | Go to Step 5 | Go to Step 4
4 | Replace the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Is the repair complete? | -- | Go to Step 6 | --
5 |

1. Install the scan tool.
2. Use the scan tool to request the SIR DTC display.
3. If a history DTC exists, refer to Diagnostic Aids for the specific DTC and diagnose the problem.
4. Replace components and perform inspections as required following an accident. Refer to Repairs and Inspections Required After a Collision .

Have the appropriate inspections and repairs been made?

--

Go to Step 6

--

6 |

1. Reconnect all SIR components.
2. Make sure that all components and connectors are properly connected and mounted.

Have all the SIR components been reconnected and properly mounted?

--

Go to SIR Diagnostic System Check

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