For 1990-2009 cars

### Circuit Description

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

Upon passing this test, ignition and deployment loop voltages are measured to ensure that they are within their normal voltage ranges. The SDM monitors the voltages at the driver low and the passenger low to detect shorts to ground or voltage in the deployment loops.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 002 Driver Air Bag Deployment Loop Resistance Too Low

### Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

### Conditions for Setting the DTC

• | The resistance of the driver air bag deployment loop is lower than 1.8 ohms.

• | The shorting bar is damaged and then the SDM must be replaced.

### 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.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Caution: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Caution in the Preface section. Caution: Refer to Sensing and Diagnostic Module Handling Caution in the Preface section. Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Examine the wiring and the connector at the steering wheel module. Is the connector disconnected? | -- | Go to Step 3 | Go to Step 4
3 | Connect the steering wheel module connector. Did you complete the repair? | -- | Go to Step 10 | --
4 |

1. Remove the steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement
2. Disconnect the electrical connector at the sensing and diagnostic module (SDM).

The shorting bar at the disconnected SDM connector will create a complete circuit between the wires from the steering wheel module.

3. Test the resistance between the steering wheel module deployment hi and low circuits.

Does the ohmmeter indicate the specified value?

∞

Go to Step 5

Go to Step 7

5 |

1. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
2. Connect the negative battery cable.
3. Use the scan tool in order to clear the DTCs.
4. Perform the Diagnostic System Check - Vehicle .

Is DTC 002 still shown as a current fault?

Go to Step 6

Go to Step 10

6 | Replace the steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement . Did you complete the repair? | -- | Go to Step 10 | --
7 |

1. Disconnect the steering wheel module coil wiring harness connector at the lower steering column.

The shorting bar at the disconnected SDM connector will create a complete circuit between the wires from the steering wheel module.

2. Test the resistance between the steering wheel module deployment hi and low circuits at the SDM side of the steering wheel module coil connector.

Does the ohmmeter show the specified value?

∞

Go to Step 8

Go to Step 9

8 | Replace the steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement . Did you complete the repair? | -- | Go to Step 10 | --
9 | Replace the supplemental inflatable restraints (SIR) wiring harness. Did you complete the repair? | -- | Go to Step 10 | --
10 |

1. Reconnect all SIR components.
2. Verify that all components, connectors and connector position assurances (CPAs) are properly mounted.
3. Use the scan tool in order to clear the DTCs.
4. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK