For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using the 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 B1451 : Manual Cut-off Switch Malfunction

### Circuit/System Description

When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform turn-on test to diagnose critical malfunctions within SDM itself.

The SDM continuously checks the disable switch position switch and circuit defect by letting the regular voltage flow through the disable switch circuit and verifying the current.

### Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

An open or short in wiring between SDM and disable switch.

### Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

• | A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

### Reference Information

#### Schematic Reference

SIR Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Testing

Note: When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.

• | The steering wheel coil module

• | The SDM module

• | The steering wheel coil module wiring harness connector

• | The SDM wiring harness connector

1. Ignition OFF, disconnect the passenger disable switch connector.
2. Disconnect the SDM connector.
3. Test for less than 1 ohm between terminal 60 of SDM and terminal 3 of disable switch.

⇒ | If resistance is not as specified, repair the open or high resistance in the circuit.

4. Connect the SDM connector.
5. Ignition ON, check for 12.5 mA at terminal 3 of disable switch.

⇒ | If amperage is greater than specified, replace the disable switch.

⇒ | If amperage is less than specified, replace the SDM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Steering Wheel Inflatable Restraint Module Coil Replacement

• | Steering Wheel Inflatable Restraint Module Replacement

• | Control Module References for SDM replacement, setup, and programming