For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC B0051 00: Squib Circuits Activated (Crash)
DTC B0053 00: Deployment Commanded With Loop DTCs Present
DTC B0055 00: Deployment Side Airbag Deployment Commanded

### Circuit/System Description

The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device that converts vehicle velocity changes into 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 2 of the generated signals exceed the stored values, the SDM will cause current to flow through the deployment loops

• | Deploying the air bags and/or pretensioners causing DTC B0051 to set.

• | Deploying the side airbags causing DTC B0055 to set with no faults present.

### Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

#### B0051 00

• | The SDM detects an impact of sufficient force to warrant deployment of the frontal modules.

• | The SDM detects an impact of sufficient force to warrant deployment of the seat pretensioner modules.

#### B0053 00

SDM commands inflators deployment with loop faults present.

#### B0055 00

The SDM detects a side impact of sufficient force to warrant deployment of a side impact module and/or roof rail module.

### Action Taken When the DTC Sets

• | The SDM will only set DTC B0051, or DTC B0055, or the SDM sets DTC B0053 along with DTC B0051.

• | The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.

• | The SDM records crash data.

### Conditions for Clearing the DTC

• | DTC B0051 can be cleared if the following conditions are met.

- | Three consecutive seat belt pretensioner deployment events have not occurred.

- | One frontal or side air bag deployment has not occurred.

• | DTC B0051 becomes a latched code after 3 consecutive pretensioner deployments or 1 frontal or side air bag deployment. The DTC is a latched code and cannot be cleared. Replace the SDM after following the instructions in the diagnostic test.

• | DTC B0055 is a latched code and cannot be cleared.

### Reference Information

#### Schematic Reference

SIR Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

SIR System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

• | Connector Repairs

#### Scan Tool Reference

Control Module References for scan tool information.

### Circuit/System Verification

Important: The seat belt pretensioners may deploy for impacts that are not severe enough to warrant frontal or side air bag deployment. The SDM is capable of sustaining 3 pretensioner deployment events, or one frontal or side deployment event. After the maximum number of deployments has occurred, DTC B0051 sets and becomes a latched code, which cannot be cleared.

1. Verify DTC B0053 is not set.

⇒ | If DTC B0053 is set along with additional DTCs, other than B0051, repair the malfunction causing the DTCs before replacing the SDM.

2. Verify DTC B0051 is not set.

⇒ | If DTC B0051 is set, clear DTCs. If the DTC sets, replace the SDM.

3. Verify DTC B0052, B0054 or B0058 are not set.

⇒ | If any of the DTCs are set, clear DTC. If DTC sets, replace the SDM.

4. Verify DTC B0055 is not set.

⇒ | If DTC B0055 is set, replace the SDM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SDM replacement, setup, and programming.