For 1990-2009 cars

### Circuit Description

The SDM contains a sensing device that converts vehicle velocity changes to an electrical signal. The electrical signal is generated by the SDM and compared to a value stored in memory. When the generated signals exceed the stored values, the SDM deploys the air bags and stores a DTC in its memory. If a deployment occurs while an inflator circuit fault is present this DTC will be set.

### DTC Test Conditions:

DTC B0053 is set when the SDM commands the inflator to deploy with a loop fault present. The following conditions must be met to set this DTC.

• | An inflator loop fault was previously detected.

• | The SDM detects a frontal crash, up to 30 degrees of the center line of the vehicle.

• | Fault needs to only be present for less than half a second or five consecutive sample readings.

• | Crash was of sufficient force to warrant deployment of air bags.

### Action Taken:

• | When this fault is detected a current DTC will be set.

• | The air bag light will be turned on.

• | DTC will be latched into SDMs memory.

### Diagnostic Aids:

Always start diagnosis of SIR DTCs with an inspection of vehicle, including its wiring and SIR components for visible damage.

Always replace SDM's with DTCB0053 set, only after all collision repairs have been completed.

An open in circuits 347 and 348 to the driver inflator module could cause this DTC.

Important: DTC B0053 is a latched code and can not be cleared from the SDM memory

Important: Perform SIR Diagnostic System Check before proceeding with this chart.

Caution: Be careful when you handle a sensing and diagnostic module (SDM). Do not strike or jolt the SDM. Before applying power to the SDM:

• | Remove any dirt, grease, etc. From the mounting surface.

• | Position the SDM horizontally on the mounting surface.

• | Tighten all of the SDM fasteners and SDM bracket fasteners to the specified torque value.

Failure to follow the correct procedures could cause air bag deployment, personal injury, or unnecessary SIR system repairs.

Step | Action | Yes | No
1 | Did you perform the Diagnostic System Check - SIR? | Go to Step 2 | Go to SIR Diagnostic System Check
2 |

1. Turn OFF the ignition switch.
2. Inspect the vehicle for deployed air bags.

Have the air bags been deployed?

Go to Step 4

Go to Step 3

3 | Inspect front of vehicle and undercarriage for signs of impact. Are there signs of impact? | Go to Step 6 | Go to Step 5
4 |

1. Turn OFF the ignition.
2. Replace all damaged components.

Are the repairs complete?

Go to Step 5

--

5 |

1. Turn OFF ignition.
2. Replace the SDM.

Are the repairs complete?

Go to Step 7

--

6 |

1. Refer to Repair and Inspections Required After an Accident.
2. Replace the SDM.

Are the repairs complete?

Go to Step 7

--

7 |

1. Reconnect all components.
2. Clear all DTCs.

Was the Diagnostic System Check performed after repair?

--

Go to Step 8

8 | Perform the Diagnostic System Check. | -- | --