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 the 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 053 Left Side 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 side impact module deployment loop is lower than 1.4 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: Component Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Disconnect the driver side impact module.
2. Disconnect the connector of the sensing and diagnostic module (SDM).
3. Test the resistance between the driver side impact module deployment hi and low circuits on the SDM side of the connector.

Does the ohmmeter show the specified value?

∞

Go to Step 3

Go to Step 5

3 |

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

Is DTC 053 still shown as a current fault?

--

Go to Step 4

Go to Step 6

4 | Replace the driver side impact module. Did you complete the repair? | -- | Go to Step 6 | --
5 | Replace the supplemental inflatable restraints (SIR) wiring harness. Did you complete the repair? | -- | Go to Step 6 | --
6 |

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