For 1990-2009 cars
SIR Components
Seat Belt Pretensioners, Side Inflatable Restraint Modules, and Sensors
SIR Handling Caution
Handling ESD Sensitive Parts Notice

### Circuit Description

When you first turn ON the ignition, the inflatable restraint sensing and diagnostic and seat belt pretensioner module (SDM) performs tests to diagnose critical malfunctions within itself. Then, the SDM proceeds with the RESISTANCE MEASUREMENT test to measure the deployment loop resistances to ensure they are within their respective normal resistance ranges. Upon passing these tests, the energy reserve is charged and the firing transistors are tested. The SDM then goes into CONTINUOUS MONITORING mode. The SDM provides input power to the inflatable restraint side impact sensor (SIS). When input power is first detected, the SIS responds by performing internal diagnostics. Next, the SIS sends a OK/NOK message to the SDM to indicate proper operation.

### Conditions for Running the DTC

When the ignition voltage is within the normal operating voltage range, the SDM monitors the inflatable restraint side impact sensor and the circuits.

### Conditions for Setting the DTC

When the ignition voltage is within the normal operating voltage range, the measured leakage currents to voltage or the resistance of the SIS loop are above a specified value caused by:

• | A short to voltage in the SIS loop

• | An open or a high resistance in the SIS loop

### Action Taken When the DTC Sets

The SDM turns ON the AIR BAG warning lamp.

### Conditions for Clearing the DTC

• | Current DTC

- | The SDM has detected correct operation

- | The SIS sends an OK message to the SDM

• | History DTC

- | You can issue a clear codes command

- | Once 255 malfunction free ignition cycles have occurred

### Diagnostic Aids

An inflatable restraint side impact sensor (SIS) circuit open, high resistance, or short to voltage can cause an intermittent condition. Inspect the inflatable restraint side impact sensor high and sensor low circuits carefully for cutting and/or chafing.

### Test Description

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

1. This step checks the inflatable restraint side impact sensor wiring harness connector.

2. This step checks the inflatable restraint side impact sensor.

3. This step checks the SDM wiring harness connector.

4. This step checks the SDM terminals.

5. This step checks for an open or a high resistance in the inflatable restraint side impact sensor circuit.

6. This step checks for an open or a high resistance in the inflatable restraint side impact sensor return circuit.

7. This step checks for a short to B+ in the inflatable restraint side impact sensor circuit.

8. This step determines if there is a short to B+ in the inflatable restraint side impact sensor return circuit or if there is a malfunctioning inflatable restraint side impact sensor.

9. This step determines if there is a malfunctioning SDM.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
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. Disconnect the inflatable restraint side impact sensor (LH) 2-way connector. Refer to Inflatable Restraint Side Impact Sensor Replacement .
3. Inspect the SIS wiring harness connector for the following conditions:

• | Corrosion

• | Damaged terminals

• | Poor connections/terminal tension

Does the SIS wiring harness connector exhibit and signs of corrosion, terminal damage, or poor connections?

--

Go to Step 3

Go to Step 4

3 | Replace the SIS wiring harness connector. Refer to Connector Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 4 | --
4 | Inspect the SIS terminals for damaged terminals or corrosion. Does the SIS terminals exhibit any signs of corrosion or damaged terminals? | -- | Go to Step 18 | Go to Step 19
5 | Inspect the SIS terminals for damaged terminals or corrosion. Does the SIS terminals exhibit any signs of corrosion or damaged terminals? | -- | Go to Step 18 | Go to Step 6
6 |

1. Disconnect the inflatable restraint sensing and diagnostic and seat belt pretensioner module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic and Seat Belt Pretensioner Module Replacement .
2. Inspect the SDM wiring harness connector for the following conditions:

• | Corrosion

• | Damaged terminals

• | Poor connections/terminal tension

Does the SDM wiring harness connector exhibit any signs of corrosion, damaged terminals, or poor connections?

--

Go to Step 7

Go to Step 8

7 | Replace the SDM wiring harness connector. Refer to Connector Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 8 | --
8 | Inspect the SDM terminals for corrosion or damaged terminals. Does the SDM exhibit any sings of corrosion or damaged terminals? | -- | Go to Step 20 | Go to Step 21
9 | Inspect the SDM terminals for corrosion or damaged terminals. Does the SDM exhibit any sings of corrosion or damaged terminals? | -- | Go to Step 20 | Go to Step 10
10 |

1. Zero the J 39200 Digital Multimeter (DMM).
2. Use the DMM to measure the resistance of the inflatable restraint side impact sensor circuit.

Does the resistance measure less than the specified value?

0.5 ohms

Go to Step 12

Go to Step 11

11 | Locate and repair an open or a high resistance in the inflatable restraint side impact sensor circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 19 | --
12 | Use the DMM to measure the resistance of the inflatable restraint side impact sensor return circuit. Does the resistance measure less than the specified value? | 0.5 ohms | Go to Step 14 | Go to Step 13
13 | Locate and repair an open or a high resistance in the inflatable restraint side impact sensor return circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 19 | --
14 |

1. Turn ON the ignition, with the engine OFF.
2. Use the DMM to measure the voltage between the inflatable restraint side impact sensor circuit and a known good ground.

Does the voltage measure less than the specified value?

1 V

Go to Step 16

Go to Step 15

15 | Locate and repair the short to B+ in the inflatable restraint side impact sensor circuit. Did you complete the repair? | -- | Go to Step 19 | --
16 | Use the DMM to measure the voltage between the inflatable restraint side impact sensor return circuit and a known good ground. Does the voltage measure less than the specified value? | 1 V | Go to Step 18 | Go to Step 17
17 | Locate and repair the short to B+ in the inflatable restraint side impact sensor return circuit. Did you complete the repair? | -- | Go to Step 19 | --
18 |

1. Turn OFF the ignition.
2. Replace the inflatable restraint side impact sensor. Refer to Inflatable Restraint Side Impact Sensor Replacement .

Did you complete the replacement?

--

Go to Step 19

--

19 |

1. Reconnect all SIR components.
2. Verify that all components and connectors are properly mounted.
3. Turn ON the ignition, with the engine OFF.
4. Use the scan tool to request the SIR DTC display.

Does the scan tool indicate that this DTC is current?

--

Go to Step 20

Go to Diagnostic System Check - SIR

20 |

1. Turn OFF the ignition.
2. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic and Seat Belt Pretensioner Module Replacement .

Did you complete the replacement?

--

Go to Step 21

--

21 |

1. Reconnect all SIR components.
2. Verify that all components and connectors are properly mounted.
3. Turn ON the ignition, with the engine OFF.
4. Use the scan tool in order to clear the DTCs.

Did you complete the action?

--

Go to Diagnostic System Check - SIR

--