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

### Circuit Description

When you first turn the ignition switch to the ON position, the inflatable restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. Next the SDM measures IGNITION 1 voltage to make sure it is within its respective normal voltage ranges. Then the SDM proceeds with the DEPLOYMENT LOOP CONTINUITY test. During the DEPLOYMENT LOOP CONTINUITY test, the SDM measures the voltage difference between DRIVER SIDE HIGH and the DRIVER SIDE LOW.

### Conditions for Setting the DTC

• | The voltage difference between the DRIVER SIDE HIGH terminal 9 and DRIVER SIDE LOW terminal 10 is more than or equal to 400 millivolts.

• | The malfunction must be present for at least 500 milliseconds during one of the following tests:

- | If the malfunction is detected in the DEPLOYMENT CONTINUITY test, the RESISTANT MEASUREMENT test will not be performed.

- | The CONTINUOUS MONITORING test.

### 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

• | Clear the Current DTC when the voltage difference between the DRIVER SIDE HIGH terminal 9 and DRIVER SIDE LOW terminal 10 is less than 400 millivolts for 500 milliseconds.

• | Clear the HISTORY DTC under the following conditions:

- | You issue a scan tool CLEAR CODES command.

- | 250 malfunction free ignition cycles have occurred.

### Diagnostic Aids

The following can cause an intermittent condition:

• | A poor connection at the inflatable restraint steering wheel module steering column connector terminal 1 and terminal 2.

• | A poor connection at the upper inflatable restraint steering wheel module coil connector terminal 1 and terminal 2.

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 in this section.

### DTC Table Test Description

Numbers below refer to step numbers on the diagnostic table.

1. This step determines the deployment loop voltage difference measured by the SIR Sensing and Diagnostic Module (SDM).

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

3. This step isolates the malfunction to one side of the yellow 2-way connector on the inflatable restraint steering wheel module. This connector is located near the base of the steering column.

4. This step determines whether the malfunction is in the inflatable restraint steering wheel module coil or in the inflatable restraint steering wheel module.

5. This step checks for proper contact or corrosion of the SDM connector.

6. This step checks for proper contact or corrosion of the SDM connector.

7. This test determines whether the malfunction is in the GRN/RED wire.

8. This test determines whether the malfunction is in the GRN wire.

#### DTC B1026 Driver Deployment Loop Open

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 LOCK position.
2. Connect a scan tool to the data link connector. Follow the directions in the instruction manual of the scan tool.
3. Turn the ignition switch to the ON position.
4. Request the SIR data list display.
5. Read the driver deployment loop voltage difference DRIVER VDIF. Record the value on the repair order.

Have you read the DRIVER VDIF and recorded the value on the repair order?

--

Go to Step 3

--

3 |

1. Turn the ignition switch to the LOCK position.
2. Disconnect the yellow connectors on the inflatable restraint steering wheel module and on the inflatable restraint IP module. These connectors are located near the base of the steering column and behind the IP compartment.
3. Check for proper connection at terminal 1 and terminal 2 on the harness side of the yellow 2-way connector on the inflatable restraint steering wheel module. This connector is located at the base of the steering column.

Are the terminals damaged or corroded?

--

Go to Step 4

Go to Step 6

4 | Replace the yellow 2-way harness connector at the base of the steering column. Refer to SIR Connector (Plastic Body and Terminal Metal Pin) Repair portion of Wiring Repair . Have you replaced the yellow 2-way harness connector? | -- | Go to Step 5 | --
5 | Check for a proper connection at the terminal 1 and terminal 2 on the inflatable restraint steering wheel module coil side of the 2-way connector. Are the terminals damaged or corroded? | -- | Go to Step 7 | Go to Step 23
6 | Check for a proper connection at the terminal 1 and terminal 2 on the inflatable restraint steering wheel module coil side of the 2-way connector. Are the terminals damaged or corroded? | -- | Go to Step 7 | Go to Step 8
7 | Replace the inflatable restraint steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement - Off Vehicle in Steering Wheel and Column-Standard. Have you replaced the inflatable restraint steering wheel module coil? | -- | Go to Step 23 | --
8 |

1. Reconnect the yellow connectors on the inflatable restraint steering wheel module and on the inflatable restraint IP module.
2. Turn the ignition switch to the ON position.
3. Using the scan tool, request the SIR data list display. Read the driver deployment loop voltage difference DRIVER VDIF.

Is DRIVER VDIF more than the specified value?

400 mV

Go to Step 10

Go to Step 9

9 |

1. Turn the ignition switch to the LOCK position.
2. Replace the yellow 2-way harness connector at the base of the steering column. Refer to SIR Connector (Plastic Body and Terminal Metal Pin) Repair portion of Wiring Repair .

Have you replaced the yellow 2-way harness connector?

Go to Step 23

--

10 |

1. Turn the ignition switch to the LOCK position.
2. Disconnect the yellow 2-way connectors on the inflatable restraint steering wheel module and on the inflatable restraint IP module. These connectors are located near the base of the steering column and behind the IP compartment.
3. Connect the J 38715-A SIR Driver/Passenger Load Tool to the inflatable restraint steering wheel module connector and to the inflatable restraint IP module harness connector.
4. Turn the ignition switch to the ON position.
5. Using the scan tool, request the SIR data list display. Read the driver deployment loop voltage difference DRIVER VDIF.

Is DRIVER VDIF more than the specified value?

400 mV

Go to Step 14

Go to Step 11

11 |

1. Turn the ignition switch to the LOCK position.
2. Remove the inflatable restraint steering wheel module from the steering wheel. Refer to Steering Wheel Inflator Module Replacement in Steering Wheel and Column-Standard.
3. Disconnect the J 38715-A from the 2-way connector at the base of the steering column.
4. Reconnect the 2-way connector at the base of the steering column.
5. Connect the J 38715-A to the inflatable module connector on the steering column.
6. Turn the ignition switch to the ON position.
7. Using the scan tool, request the SIR data list display. Read the driver deployment loop resistance DRIVER VDIF.

Is DRIVER VDIF more than the specified value?

400 mV

Go to Step 13

Go to Step 12

12 |

1. Turn the ignition switch to the LOCK position.
2. Replace the inflatable restraint steering wheel module. Refer to Steering Wheel Inflator Module Replacement in Steering Wheel and Column-Standard.

Have you replaced the inflatable restraint steering wheel module?

--

Go to Step 23

--

13 |

1. Turn the ignition switch to the LOCK position.
2. Replace the inflatable restraint steering wheel module coil. Refer to Steering Wheel Inflator Module Replacement in Steering Wheel and Column-Standard.

Have you replaced the inflatable restraint steering wheel module coil?

--

Go to Step 23

--

14 |

1. Turn the ignition switch to the LOCK position.
2. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM).
3. Disconnect the J 38715-A .
4. Check for a proper connection at terminal 9 and terminal 10 on the harness side of the SDM connector.

Is the SDM harness connector damaged or corroded?

--

Go to Step 15

Go to Step 17

15 | Replace the SDM harness connector. Refer to SIR Connector (Plastic Body and Terminal Metal Pin) Repair portion of Wiring Repair . Have you replaced the SDM harness connector? | -- | Go to Step 16 | --
16 | Check for a proper connection at terminal 9 and 10 on the SDM. Are the SDM terminals damaged or corroded? | -- | Go to Step 18 | Go to Step 23
17 | Check for a proper connection at terminal 9 and terminal 10 on the SDM. Are the SDM terminals damaged or corroded? | -- | Go to Step 18 | Go to Step 19
18 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Have you replaced the SDM? | -- | Go to Step 23 | --
19 |

1. Zero the J 39200 .
2. Measure the resistance from the SDM harness connector terminal 9 to the inflatable restraint steering wheel module 2-way harness connector terminal 2.

Is the resistance reading within the specified values?

0-0.5ohms

Go to Step 21

Go to Step 20

20 | Repair the high resistance in the GRN/RED wire. Have you repaired the circuit? | -- | Go to Step 23 | --
21 |

1. Zero the J 39200 .
2. Measure the resistance from the SDM harness connector terminal 10 to the inflatable restraint steering wheel module 2-way harness connector terminal 1.

Is the resistance reading within the specified values?

0-0.5ohms

Go to Integrity Check

Go to Step 22

22 | Repair the high resistance in the GRN wire. Have you repaired the circuit? | -- | Go to Step 23 | --
23 | Reconnect and confirm that all of the SIR system components are properly mounted. Are all the SIR components connected and properly mounted? | -- | Go to Step 24 | --
24 | Clear the SIR diagnostic trouble codes. Have you cleared the SIR Diagnostic trouble codes? | -- | Go to SIR Diagnostic System Check | --