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

### Circuit Description

When you first turn the ignition switch to the RUN position, the inflatable restraint sensing and diagnostic module (SDM) performs tests in order to diagnose critical malfunctions within the module. Next the SDM measures the ignition positive voltage and the deployment loop voltages in order to ensure that the voltages are within the respective normal voltage ranges. The SDM proceeds with the resistance measurement test. During 1 portion of the resistance measurement test, the SDM performs the following functions:

• | Grounds the DRIVER LOW terminal 3 through an internal current sink.

• | Connects the DRIVER HIGH terminal 2 to an internal constant current source. This current produces proportional voltage drops in the deployment loop.

• | Measures the voltage difference between the DRIVER HIGH and the DRIVER LOW.

• | Calculates the resistance of the driver deployment loop using the measured voltage.

### Conditions for Setting the DTC

• | The driver and passenger deployment loops are not open.

• | The driver and passenger deployment loops are not shorted to voltage.

• | The driver deployment loop is not shorted to ground.

• | The driver deployment loop resistance is less than 1.7 ohms. The driver deployment loop consists of the following components:

- | An Inflatable restraint steering wheel module

- | An Inflatable restraint steering wheel module coil

- | Harness wiring of CKT 347

- | Harness wiring of CKT 348

- | Connector terminal contact

The resistance measurement test inspects for this malfunction. This test only occurs once each ignition cycle when the ignition positive voltage is within the normal operating voltage range.

### Action Taken When the DTC Sets

• | The SDM sets a diagnostic trouble code.

• | The SDM turns ON the AIR BAG Warning Indicator.

### Conditions for Clearing the MIL/DTC

• | Current DTC

| The resistance of the driver deployment loop is more than 1.7 ohms and the ignition switch is cycled.

• | History DTC

- | You issue a scan tool CLEAR CODES command.

- | 250 malfunction free ignition cycles have occurred.

When you issue a scan tool CLEAR CODES command and the malfunction is still present, the DTC will not reappear until the next ignition cycle.

### Diagnostic Aids

The following conditions may cause an intermittent condition:

• | A short circuit between CKT 347 and CKT 348

• | A short circuit between CKT 347 and CKT 1403

• | A short circuit between CKT 347 and CKT 1404

• | A malfunctioning shorting bar on the inflatable restraint steering wheel module connector

• | A malfunctioning shorting bar on the inflatable restraint steering wheel module coil steering column connector

The diagnostic table directs the technician in order to note the entry value of the driver resistance. Comparing the value of driver resistance over multiple ignition cycles may be helpful in determining if an intermittent condition exists.

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 the deployment loop resistance measured by the inflatable restraint Sensing and Diagnostic Module (SDM).

2. This test isolates the malfunction to one side of the inflatable restraint steering wheel module coil yellow 2-way connector.

3. This test determines whether the malfunction is due to the inflatable restraint steering wheel module or the module coil.

4. This test checks for a short from CKT 347 to CKT 348.

5. This test checks for a short from CKT 347 to CKT 1404.

#### DTC B1022 Driver Deployment Loop Resistance Low

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. Connect a scan tool.
3. Turn the ignition switch to the RUN position, engine off.
4. Request the SIR data list display.
5. Read and record on the repair order the driver deployment loop resistance DRIVER RESISTANCE.
6. Request the SIR DTC display.

Is DTC B1016 also present?

--

Go to Step 3

Go to Step 4

3 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint steering wheel and IP module yellow 2-way connectors at the base of the steering column and above the RH sound insulator.
3. Repair the short from CKT 347 to CKT 1403.

Is the repair complete?

--

Go to Step 14

--

4 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint steering wheel module yellow 2-way connector at the base of the steering column.
3. Reconnect the 2-way connector.
4. Inspect that the CPA is properly installed.
5. Turn the ignition switch to the RUN position.
6. Using a scan tool, request the SIR data list display.
7. Read the driver deployment loop resistance DRIVER RESISTANCE.

Is DRIVER RESISTANCE less than the specified value?

1.7 ohms

Go to Step 6

Go to Step 5

5 |

1. Turn the ignition switch to the OFF position.
2. Replace the yellow 2-way harness connector at the base of the steering column. Refer to Wiring Repair .

Is the repair complete?

--

Go to Step 14

--

6 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint steering wheel and IP module yellow 2-way connectors at the base of the steering column and above the LH sound insulator.
3. Connect J 38715-A SIR Driver/Passenger Load Tool to the harness connectors.
4. Turn the ignition switch to the RUN position.
5. Using the scan tool, request the SIR data list display.
6. Read the driver deployment loop resistance DRIVER RESISTANCE.

Is DRIVER RESISTANCE less than the specified value?

1.7 ohms

Go to Step 10

Go to Step 7

7 |

1. Turn the ignition switch to the OFF position.
2. Remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
3. Disconnect J 38715-A Load Tool from the driver 2-way harness connector.
4. Connect the driver 2-way connector at the base of the steering column.
5. Connect J 38715-A Load Tool to the upper inflatable restraint steering wheel module coil connector on the steering column.
6. Turn the ignition switch to the RUN position.
7. Using the scan tool, request the SIR data list display.
8. Read the driver deployment loop resistance DRIVER RESISTANCE.

Is DRIVER RESISTANCE less than the specified value?

1.7 ohms

Go to Step 9

Go to Step 8

8 |

1. Turn the ignition switch to the OFF position.
2. Replace the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .

Is the repair complete?

--

Go to Step 14

--

9 |

1. Turn the ignition switch to the OFF position.
2. Replace the inflatable restraint steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .

Is the repair complete?

--

Go to Step 14

--

10 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM).
3. Disconnect J 38715-A Load Tool.
4. Using J 39200 DMM, measure the resistance between SDM harness connector terminals 2 and 3.

Is the resistance reading less than the specified value?

OL

Go to Step 11

Go to Step 12

11 | Repair a short from CKT 347 to CKT 348. Is the repair complete? | -- | Go to Step 14 | --
12 | Using J 39200 DMM, measure the resistance between SDM harness connector terminals 2 and 4. Is the resistance reading less than the specified value? | OL | Go to Step 13 | Go to Sensing and Diagnostic Module Integrity Check
13 | Repair a short from CKT 347 to CKT 1404. Is the repair complete? | -- | Go to Step 14 | --
14 | Reconnect all the SIR system components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | Go to Step 15 | --
15 | Clear all the SIR DTCs. Have all the SIR DTCs been cleared? | -- | Go to SIR Diagnostic System Check | --