For 1990-2009 cars
SIR Components
SIR Schematics
SIR Caution
Handling ESD Sensitive Parts Notice
SIR Caution
SIR Caution
SIR Caution

### Circuit Description

The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device that converts 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. DTC B1053 will set instead of a DTC B1051 when a deployment occurs while an inflator circuit fault is present that could possibly result in a non-deployment situation in one or both inflator modules.

### 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 air bags.

### Action Taken When the DTC Sets

• | The SDM sets a Diagnostic Trouble Code.

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

• | The SDM records crash data.

### Conditions for Clearing the DTC

DTC B1053 is a latched code. You cannot clear a latched code. Replace the SDM after following the instructions in the diagnostic table.

### Diagnostic Aids

DTC B1053 will be accompanied by another DTC (other than DTC B1071). Repair the malfunction causing the other DTC(s) 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 B1053 may have set falsely.

2. If DTC B1053 has set with no signs of frontal impact, the DTC has set falsely.

#### DTC B1053 Deployment Commanded w/Loop Malfunction

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. Have the inflator modules 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 . Are the repairs complete? | -- | Go to Step 6 | --
5 | 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 | Reconnect all the SIR system components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | Go to SIR Diagnostic System Check | --