B0026

Circuit Description

When you first turn the ignition switch to the RUN position, the Inflatable Restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. Then the SDM performs the following continuous diagnostic tests on the deployment loops:

^ Deployment loop voltage out of range test

^ Deployment loop resistance measurement test

If the voltage out of range test detects a short to voltage condition, the resistance measurement test for that deployment loop will not be performed.

Conditions for Setting the DTC

^ Deployment loop voltage out of range test.

- Ignition 1 voltage is within the normal operating voltage range.

- Driver frontal deployment loop is not shorted to voltage.

- Driver frontal high terminal A6 is less than 2 volts.

- Driver frontal deployment loop resistance is at least 6 ohms for 300 milliseconds.

^ Deployment loop resistance measurement test.

- Ignition 1 voltage is within the normal operating voltage range.

- Driver frontal deployment loop is not shorted to voltage.

- Driver frontal deployment loop is not shorted to ground.

- Driver frontal deployment loop resistance is more than 4.8 ohms for 300 milliseconds.

The driver frontal deployment loop consists of the following components:

^ Inflatable Restraint Steering Wheel Module.

^ Inflatable Restraint Steering Wheel Module Coil.

^ Harness wiring of circuit 347.

^ Harness wiring of circuit 348.

^ Connector terminal contact.

Action Taken When the DTC Sets

^ The SDM sets a DTC B0026.

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

Conditions for Clearing the DTC

^ Current DTC

- Deployment loop voltage out of range test-Driver frontal high terminal A6 is more than 2 volts AND driver frontal deployment loop resistance is less than 6 ohms for 300 milliseconds.

- Deployment loop resistance measurement test-Driver frontal deployment loop resistance is no more than 4.8 ohms for 300 milliseconds.

^ History DTC

- You issue a scan tool CLEAR CODES command.

- Once 250 malfunction free ignition cycles have occurred.

Diagnostic Aids

A poor connection can cause an intermittent condition. Check the following for a poor connection:

^ The Inflatable Restraint Steering Wheel Module 2-way connector terminal A and terminal B.

^ The inline connector C215.

^ The SDM terminal A6 and terminal A7.

^ The wire to terminal connections in circuit 347.

^ The wire to terminal connections in circuit 348.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

2. This step checks the inline connector C215.

6. This step determines if the Inflatable Restraint Steering Wheel Module Coil or if the Inflatable Restraint Steering Wheel Module is defective.

9. This step checks to see if the SDM wiring harness connector is OK.

11. This step checks to see if there is an open or a high resistance in circuit 347.

13. This step determines if there is an open or a high resistance in circuit 348 or if there is a malfunctioning SDM.