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

### Circuit Description

The inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself when the ignition switch is turned ON. The SDM monitors the six firing loops to detect leakage currents to ground and system voltage in the frontal and side air bag inflator module and seat belt pretensioner circuits. The deployment loop resistances are measured to ensure they are within their respective normal resistance ranges. Upon passing these tests, and if the energy reserve is charged up, the firing transistors are tested. The SDM then goes into Continuous Monitoring mode. Refer to On-Vehicle Service for enable/disable procedures.

### Conditions for Setting the DTC

DTC B1045 will set once the following conditions are met. This test is run during the SDM Turn-ON tests.

• | The ignition is within normal operating voltage range.

• | An internal fault in the driver side impact sensor (SIS).

• | An open circuit condition in the driver side impact sensor (SIS) circuit.

• | A short circuit condition in the driver side impact sensor (SIS) circuit.

• | A short to ground condition in the driver side impact (SIS) circuit.

• | A short to voltage condition in the driver side impact sensor (SIS) circuit.

The driver side impact sensor (SIS) loop consists of the following components:

• | The inflatable restraint side impact sensor (LH) .

• | The harness wiring of CKT 2131.

• | The harness wiring of CKT 2132.

• | The connector terminal contact.

### 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

Current and History DTC codes must be cleared using a scan tool Clear DTC Information command. If the circuit fault has been successfully repaired and the conditions which caused the Current DTC B1045 to set are no longer existing, History DTC B1045 will set. History DTC B1045 may be cleared using the scan tool.

### Diagnostic Aids

An inflatable restraint driver side impact sensor (SIS) circuit short to ground can cause an intermittent condition. Inspect CKT 2131 and CKT 2132 carefully for cutting and/or chafing. A careful inspection of the circuits and components indicated on the DTC B1045 Table is essential to make sure that the replacement SDM will not be damaged.

When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616 Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections . When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair .

### Test Description

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

1. This test determines if the sensor is damaged.

2. This test checks for proper contact or corrosion of the yellow 2-way connector.

3. This test checks for proper contact or corrosion of the SDM harness connector.

4. This test checks for an open circuit or high resistance condition in CKT 2132

5. This test checks for an open circuit or high resistance condition in CKT 2131.

6. This test checks for a short between CKT 2131 and CKT 2132.

7. This test checks for a short to ground condition in CKT 2131.

8. This test checks for an short to ground condition in CKT 2132.

9. This test checks for a short to voltage condition in CKT 2132.

10. This test checks for a short to voltage condition in CKT 2131.

#### DTC B1045 Driver Side Impact Sensor Comms Invalid

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. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint side impact sensor (LH) yellow 2-way connectors located on the B-pillar.
3. Inspect the sensor and check for proper connection at terminals A and B on the body harness side of the inflatable restraint side impact sensor (LH).

Is the sensor damaged or are the sensor terminals damaged or corroded?

--

Go to Step 3

Go to Step 5

3 | Replace the inflatable restraint side impact sensor (LH). Refer to Inflatable Restraint Side Impact Sensor Replacement . Are the repairs complete? | -- | Go to Step 4 | --
4 | Check for proper connection at terminals A and B on the body harness side of the inflatable restraint side impact sensor (LH) yellow 2-way connector. Are the terminals damaged or corroded? | -- | Go to Step 6 | Go to Step 28
5 | Check for proper connection at terminals A and B on the body harness side of the inflatable restraint side impact sensor (LH) yellow 2-way connector. Are the terminals damaged or corroded? | -- | Go to Step 6 | Go to Step 7
6 | Replace the inflatable restraint side impact sensor (LH) yellow 2-way body harness connector. Refer to Wiring Repair . Are the repairs complete? | -- | Go to Step 28 | --
7 |

1. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM).
2. Check for proper connection at terminals 41 and 42 on the SDM harness connector.

Is the harness connector damaged or corroded?

--

Go to Step 8

Go to Step 10

8 | Replace the SDM connector. Refer to Wiring Repair . Are the repairs complete? | -- | Go to Step 9 | --
9 | Check for proper connection at terminals 41 and 42 on the SDM. Are the terminals damaged or corroded? | -- | Go to Step 11 | Go to Step 28
10 | Check for proper connection at terminals 41 and 42 on the SDM. Are the terminals damaged or corroded? | -- | Go to Step 11 | Go to Step 12
11 | Replace the inflatable restraint Sensing and Diagnostic Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Are the repairs complete? | -- | Go to Step 28 | --
12 |

1. Zero the J 39200 Digital Multimeter.
2. Measure the resistance from the SDM harness connector terminal 42 to the inflatable restraint side impact sensor (LH) yellow 2-way harness connector terminal A.

Is the resistance reading within the specified values?

0-0.5 ohms

Go to Step 14

Go to Step 13

13 | Repair the high resistance condition in CKT 2132. Are the repairs complete? | -- | Go to Step 28 | --
14 |

1. Zero the J 39200 Digital Multimeter.
2. Measure the resistance from the SDM harness connector terminal 41 to the inflatable restraint side impact sensor (LH) yellow 2-way harness connector terminal B.

Is the resistance reading within the specified values?

0-0.5 ohms

Go to Step 16

Go to Step 15

15 | Repair the high resistance condition in CKT 2131. Are the repairs complete? | -- | Go to Step 28 | --
16 |

1. Zero the J 39200 Digital Multimeter.
2. Measure the resistance from the inflatable restraint side impact sensor (LH) yellow 2-way harness connector terminal A to terminal B.

Is the resistance reading within the specified values?

0-0.5 ohms

Go to Step 17

Go to Step 18

17 | Repair the short circuit condition between CKT 2131 and CKT 2132. Are the repairs complete? | -- | Go to Step 28 | --
18 |

1. Zero the J 39200 .
2. Measure the resistance from the SDM harness connector terminal 41 to terminal 7 (ground).

Is the resistance reading less than the specified value?

OL

Go to Step 19

Go to Step 20

19 | Repair the short to ground condition in CKT 2131. Are the repairs complete? | -- | Go to Step 28 | --
20 |

1. Zero the J 39200 .
2. Measure the resistance from the SDM harness connector terminal 42 to terminal 7 (ground).

Is the resistance reading less than the specified value?

OL

Go to Step 21

Go to Step 22

21 | Repair the short to ground condition in CKT 2132. Are the repairs complete? | -- | Go to Step 28 | --
22 |

1. Turn the ignition switch to the RUN position.
2. Measure the voltage on the SDM harness connector terminal 42 to terminal 7 (ground).

Is the voltage reading less than the specified value?

1 V

Go to Step 24

Go to Step 23

23 | Repair the short to voltage condition in CKT 2132. Are the repairs complete? | -- | Go to Step 28 | --
24 |

1. Zero the J 39200 .
2. Measure the voltage on the SDM harness connector terminal 41 to terminal 7 (ground).

Is the voltage reading less than the specified value?

1 V

Go to Step 26

Go to Step 25

25 | Repair the short to voltage condition in CKT 2131. Are the repairs complete? | -- | Go to Step 28 | --
26 |

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

Are the repairs complete?

--

Go to Step 27

--

27 | Clear all the SIR DTCs. Have all the DTCs been cleared? | -- | Go to SIR Diagnostic System Check | Go to Integrity Check
28 | Reconnect all the SIR components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | Go to Step 29 | --
29 | Clear all the SIR DTCs. Have all the DTCs been cleared? | -- | Go to SIR Diagnostic System Check | --