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 deploy loops.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 024 Battery Voltage Low

### Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

### Conditions for Setting the DTC

The voltage supplied from the battery is lower than 10.6 volts.

### 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
--- | --- | --- | --- | ---
Warning: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Warning in the Preface section. Warning: Refer to Sensing and Diagnostic Module Handling Warning 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 | Inspect the fuse F1. Is the fuse open? | -- | Go to Step 3 | Go to Step 4
3 | Repair the power supply and the wiring to fuse F1. Did you complete the repair? | -- | Go to Step 11 | --
4 |

1. Turn the ignition ON.
2. Measure the voltage at the fuse F1.

Does the voltage measure less than specified?

10.6 V

Go to Step 5

Go to Step 6

5 | Repair the power supply to the fuse F1. Did you complete the repair? | -- | Go to Step 11 | --
6 |

1. Turn the ignition OFF.
2. Disconnect the connector at the sensing and diagnostic module (SDM).
3. Turn the ignition ON.
4. Measure the voltage at the terminal 5 of the SDM connector.

Does the voltage measure less than specified?

10.6 V

Go to Step 5

Go to Step 7

7 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement. Did you complete the repair? | -- | Go to Step 11 | --
8 |

1. Disconnect the connector C207.

The connector C207 is the connector between the instrument harness and the supplemental inflatable restraints (SIR) harness.

2. Turn the ignition ON.
3. Measure the voltage on the instrument harness side at the terminal 1 of the connector C207.

Does the voltage measure less than specified?

10.6 V

Go to Step 10

Go to Step 9

9 | Replace the SIR wiring harness. Did you complete the repair? | -- | Go to Step 11 | --
10 | Repair the open circuit between the fuse F1 and the connector C207. Did you complete the repair? | -- | Go to Step 11 | --
11 |

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