For 1990-2009 cars
SIR Components
SIR Schematics
SIR Caution
SIR Caution
Handling ESD Sensitive Parts Notice

### Circuit Description

When you first turn the ignition switch to the ACC or ON position, the inflatable restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM contains a resistor network connected to the SDM front-end sensor signal terminals 5 and 6. The resistor in the inflatable restraint front end discriminating sensor parallel to the normally open switch provides a parallel path to ground. This causes a specified percentage of voltage to appear at the SDM front-end sensor signal input. The SDM monitors this voltage to detect malfunctions in the discriminating sensor.

### Conditions for Setting the DTC

The SDM will set DTC 15 if it detects an open or a short in the RH front end discriminating sensor circuits.

### Action Taken When the DTC Sets

• | The SDM sets a Diagnostic Trouble Code.

• | The SDM turns ON the AIR BAG warning lamp.

### Conditions for Clearing the DTC

All DTCs are cleared with each ignition cycle.

### Diagnostic Aids

A short to ground in the inflatable restraint front end discriminating sensor circuit can cause an intermittent condition. Inspect the BRN/WHT and BLK/WHT wires carefully for cut or chafed wires.

When measurements are requested in this table, use the J 39200 DMM with the correct terminal adapter from the J 35616 Connector Test Adapter Kit. When an inspection for proper connection is requested, refer to Testing for Electrical Intermittents in Wiring Systems. When a wire, connector or terminal repair is requested, use the J-38125 Terminal Repair Kit and refer to Wiring Repairs in Wiring Systems.

### Test Description

1. This test checks for an open in the inflatable restraint right front discriminating sensor circuit.

2. This test checks for a short to ground in the inflatable restraint right front discriminating sensor circuit.

3. This test checks for a short to voltage in the inflatable restraint right front discriminating sensor feed circuit.

4. This test checks the inflatable restraint right front discriminating sensor for the proper resistance value.

5. This test checks for a short between the inflatable restraint right front discriminating sensor feed and return circuits.

6. This test checks the BLK/WHT wire for an open or high resistance condition.

7. This test checks the BRN/WHT wire for an open or high resistance condition.

8. This test checks the BRN/WHT wire for a short to ground condition.

9. This test checks the BLK/WHT wire for a short to ground condition.

10. This test checks the BRN/WHT wire for a short to voltage condition.

11. This test checks the BLK/WHT wire for a short to voltage condition.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | Go to SIR Diagnostic System Check
2 |

1. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM) connector C2.
2. Measure the resistance between the SDM connector C2 terminals 5 and 6.

Is the resistance measured within the specified range?

754-886 ohms

Go to Step 3

Go to Step 5

3 | Measure the resistance between the SDM connector C2 terminal 5 and ground. Is the resistance measured equal to the specified value? | OL (Infinite) | Go to Step 4 | Go to Step 9
4 |

1. Turn the ignition switch to the ON position.
2. Measure the voltage between the SDM connector C2 terminal 5 and ground.

Is the voltage measured less than the specified value?

1 V

Go to Step 13

Go to Step 11

5 |

1. Disconnect the inflatable restraint right front end discriminating sensor connector.
2. Measure the resistance between the inflatable restraint right front end discriminating sensor connector terminals 1 and 2.

Is the resistance measured within the specified value?

754-886 ohms

Go to Step 6

Go to Step 14

6 | Measure the resistance between the SDM connector C2 terminals 5 and 6. Is the resistance measured equal to the specified value? | OL (Infinite) | Go to Step 7 | Go to Step 16
7 |

1. Zero the J 39200 .
2. Measure the resistance between the inflatable restraint right front end discriminating sensor connector terminal 2 and the SDM terminal 6.

Is the resistance measured within the specified value?

0-0.5ohms

Go to Step 8

Go to Step 18

8 |

1. Zero the J 39200 .
2. Measure the resistance between the inflatable restraint right front end discriminating sensor terminal 1 and the SDM connector C2 terminal 5.

Is the resistance measured within the specified range?

0-0.5ohms

Go to Intermittents and Poor Connections

Go to Step 19

9 |

1. Disconnect the inflatable restraint right front end discriminating sensor connector.
2. Measure the resistance between the SDM connector C2 terminal 5 and ground.

Is the resistance measured equal to the specified value?

OL

(Infinite)

Go to Step 10

Go to Step 15

10 | Measure the resistance between the SDM connector C2 terminal 6 and ground. Is the resistance measured equal to the specified value? | OL (Infinite) | Go to Intermittents and Poor Connections | Go to Step 17
11 |

1. Disconnect the inflatable restraint right front end discriminating sensor connector.
2. Turn the ignition switch to the ON position.
3. Measure the voltage between the SDM connector C2 terminal 5 and ground.

Is the voltage measured less than the specified value?

1 V

Go to Step 12

Go to Step 20

12 | Measure the voltage between the SDM connector C2 terminal 6 and ground. Is the voltage measured less than the specified value? | 1 V | Go to Intermittents and Poor Connections | Go to Step 21
13 | Replace the Inflatable Restraint Sensing and Diagnostic Module. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Are the repairs complete? | -- | Go to Step 22 | --
14 | Replace the inflatable restraint right front end discriminating sensor. Refer to Inflatable Restraint Front End Discriminating Sensor Replacement . Are the repairs complete? | -- | Go to Step 22 | --
15 | Repair a short to ground in the BRN/WHT wire between the SDM and the front end discriminating sensor. Refer to Wiring Repair in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | --
16 | Repair a short condition between the BRN/WHT and BLK/WHT wires between the SDM and the front end discriminating sensor. Refer to Wiring Repair in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | --
17 | Repair a short to ground in the BLK/WHT wire between the SDM and the front end discriminating sensor. Refer to Wiring Repair in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | --
18 | Repair an open or high resistance condition in the BLK/WHT wire between the SDM and the front end discriminating sensor. Refer to Wiring Repair in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | --
19 | Repair an open or high resistance condition in the BRN/WHT wire between the SDM and the front end discriminating sensor. Refer to Wiring Repair in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | --
20 | Repair a short to voltage in the BRN/WHT wire between the SDM and the front end discriminating sensor. Are the repairs complete? | -- | Go to Step 22 | --
21 | Repair a short to voltage in the BLK/WHT wire between the SDM and the front end discriminating sensor. Are the repairs complete? | -- | Go to Step 22 | --
22 | Reconnect all SIR components. Make sure all components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | Go to SIR Diagnostic System Check | --