For 1990-2009 cars

### Circuit Description

When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. Then, the SDM provides input power to the inflatable restraint side impact sensor (SIS) - LF. When the input power is detected, the SIS responds by performing internal diagnostics. After that, the SIS sends an ID message to the SDM. The SDM will consider this to be a valid ID if the response time is less than 5 seconds after the SIS is powered up. The SIS will continually communicate a status message to the SDM. The SDM can reset the SIS by removing and applying power to it.

### Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

### Conditions for Setting the DTC

The measured leakage current to ground is above a specified value or the resistance is below a specified value in the SIS loop caused by a short to ground or a short between the side impact sensor - LF voltage circuit and the side impact sensor - LF signal circuit.

### Action Taken When the DTC Sets

• | The SDM turns the AIR BAG indicator ON.

• | The SDM attempts to reset the SIS.

### 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 255 malfunction free ignition cycles have occurred.

### Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

• | A short to ground in the side impact sensor - LF voltage circuit or in the side impact sensor - LF signal circuit

• | A short between the side impact sensor - LF voltage circuit and the side impact sensor - LF signal circuit

• | The SIS connector

• | An internal SIS malfunction

• | The SDM connector

• | An internal SDM malfunction

If an intermittent conditions exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

### Test Description

The following numbers refer to the step numbers on the diagnostic table:

1. Tests to see if the SIS connector is damaged or corroded.

2. Tests to see if the SIS terminals are damaged or corroded.

3. Tests to see if the SDM connector is damaged or corroded.

4. Tests to see if the SDM terminals are damaged or corroded.

5. Tests to see if there is a short to ground in the side impact sensor - LF voltage circuit or in the side impact sensor - LF signal circuit.

6. Tests to see if there is a short between the side impact sensor - LF voltage circuit and the side impact sensor - LF signal circuit.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: SIR Schematics
1 | Did you perform A Diagnostic System Check - SIR? | Go to Step 2 | Go to Diagnostic System Check - SIR
2 |

1. Turn OFF the ignition.
2. Remove the ignition key.
3. Disconnect the SIS connector. Refer to Inflatable Restraint Side Impact Sensor Replacement .
4. Inspect the SIS connector for damage or corrosion that may cause the malfunction.

Did you find and correct the condition?

Go to Step 10

Go to Step 3

3 | Inspect the SIS terminals for damage or corrosion that may cause the malfunction. Do the SIS terminals exhibit any signs of damage or corrosion? | Go to Step 8 | Go to Step 4
4 |

1. Disconnect the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
2. Inspect the SDM connector for damage or corrosion that may cause the malfunction.

Did you find and correct the condition?

Go to Step 10

Go to Step 5

5 | Inspect the SDM terminals for damage or corrosion that may cause the malfunction. Does the SDM exhibit any signs of damage or corrosion? | Go to Step 9 | Go to Step 6
6 | Test the side impact sensor - LF voltage circuit and the side impact sensor - LF signal circuit for a short to ground. Did you find and correct the condition? | Go to Step 10 | Go to Step 7
7 | Test the side impact sensor - LF voltage circuit and the side impact sensor - LF signal circuit for a short between the two circuits. Did you find and correct the condition? | Go to Step 10 | Go to Step 8
8 |

1. Turn OFF the ignition.
2. Remove the ignition key.
3. Replace the SIS. Refer to Inflatable Restraint Side Impact Sensor Replacement .

Did you complete the replacement?

Go to Step 10

--

9 |

1. Turn OFF the ignition.
2. Remove the ignition key.
3. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

Go to Step 10

--

10 |

1. Reconnect all SIR components.
2. Use the scan tool in order to clear the DTCs.
3. 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