For 1990-2009 cars

### Circuit Description

The inflatable restraint sensing and diagnostic module (SDM) contains sensing devices that convert vehicle velocity changes to an electrical signal. The SDM processes the generated electrical signal and compares it 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 signals 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 the seat belt pretensioners. DTC B0053 will set along with a DTC B0051 when a deployment occurs while an inflator circuit fault is present that could possibly result in a non-deployment situation in one or more inflator modules or seat belt pretensioners.

### Conditions for Running the DTC

Ignition voltage must be present to the SDM.

### 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.

• | The SDM detects a side impact crash of sufficient force to warrant deployment of a side air bag.

### Action Taken When the DTC Sets

• | The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

• | The SDM records crash data.

### Conditions for Clearing the DTC

DTC B0053 is a latched code. You cannot clear a latched code. Replace the SDM after following the instructions in the diagnostic table.

### Diagnostic Aids

DTC B0053 will be accompanied by another DTC (other than DTC B1000). Repair the malfunction causing the other DTCs before installing a new SDM.

### Test Description

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

1. If the inflator module(s) has not deployed, DTC B0053 may have set falsely.

2. If DTC B0053 has set with no signs of frontal impact, the DTC may have set falsely.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform A Diagnostic System Check - SIR? | -- | Go to Step 2 | Go to Diagnostic System Check - SIR
2 |

1. Turn OFF the ignition.
2. Inspect the vehicle for signs of inflator module(s) or seat belt pretensioner(s) deployment.

Does the vehicle show any signs of inflator module(s) or seat belt pretensioner(s) deployment?

--

Go to Step 5

Go to Step 3

3 | Inspect the front of the vehicle and the undercarriage for signs of impact/collision. Does the vehicle show any signs of impact/collision? | -- | 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 . Did you complete the replacement? | -- | Go to Step 6 | --
5 |

1. Install a scan tool.
2. Use the scan tool to request the SIR DTC display.
3. If a history DTC exists, refer to Diagnostic Aids for that 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 .

Did you complete the appropriate inspections and necessary repairs?

--

Go to Step 6

--

6 |

1. Reconnect all SIR components.
2. Verify that all components and connectors are properly mounted.
3. Turn ON the ignition, with the engine OFF.
4. Use the scan tool in order to clear the DTCs.

Did you complete the action?

--

Go to Diagnostic System Check - SIR

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