For 1990-2009 cars
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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. Then the SDM performs the following continuous diagnostic tests on the deployment loops:

• | Deployment loop voltage out of range test

• | Deployment loop resistance measurement test

If the voltage out of range test detects a short to voltage condition, the resistance measurement test for that deployment loop will not be performed.

### Conditions for Setting the DTC

• | Deployment loop voltage out of range test.

- | Ignition 1 voltage is within the normal operating voltage range.

- | Driver frontal deployment loop is not shorted to voltage.

- | Driver frontal high terminal A6 is less than 2 volts AND the driver frontal deployment loop resistance is at least 4.5 ohms for 500 milliseconds.

• | Deployment loop resistance measurement test.

- | Ignition 1 voltage is within the normal operating voltage range.

- | Driver frontal deployment loop is not shorted to voltage.

- | Driver frontal deployment loop is not shorted to ground.

- | Driver frontal deployment loop resistance is more than 4.5 ohms for 500 milliseconds.

The driver frontal deployment loop consists of the following components:

• | Inflatable restraint steering wheel module.

• | Inflatable restraint steering wheel module coil.

• | Harness wiring of the driver frontal high circuit.

• | Harness wiring of the driver frontal low circuit.

• | Connector terminal contact.

### Action Taken When the DTC Sets

• | The SDM sets a DTC B1026.

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

### Conditions for Clearing the DTC

• | Current DTC

- | Deployment loop voltage out of range test-driver frontal high terminal A6 is more than 2 volts AND driver frontal deployment loop resistance is less than 4.5 ohms for 500 milliseconds.

- | Deployment loop resistance measurement test-driver frontal deployment loop resistance is 4.5 ohms or less for 500 milliseconds.

• | History DTC

- | Issue a scan tool CLEAR CODES command.

- | Once 250 malfunction free ignition cycles have occurred.

### Diagnostic Aids

A poor connection can cause an intermittent condition. Check the following for a poor connection:

• | The inflatable restraint steering wheel module yellow 2-way connector terminal 1 and terminal 2.

• | The wiring harness side of the inflatable restraint steering wheel module yellow 2-way connector.

• | The SDM terminal A6 and terminal A7.

• | The wire to terminal connections in the driver frontal high circuit.

• | The wire to terminal connections in the driver frontal low circuit.

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. This step checks the inflatable restraint steering wheel module yellow 2-way connector.

2. This step determines if the inflatable restraint steering wheel module coil or the inflatable restraint steering wheel module is malfunctioning.

3. This step checks to see if the SDM wiring harness is connected properly at the SDM.

4. This step checks to see if there is an open or a high resistance condition in the driver frontal high circuit.

5. This step determines if there is an open or a high resistance condition in the driver frontal low circuit or if there is a malfunctioning SDM.

#### DTC B1026 Driver Frontal 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 OFF position.
2. Disconnect the inflatable restraint steering wheel module yellow 2-way connector.
3. Inspect the wiring harness side of the inflatable restraint steering wheel module yellow 2-way connector for corrosion or damaged terminals.

Are the inflatable restraint steering wheel module yellow 2-way connector and terminals free from damage and corrosion?

--

Go to Step 4

Go to Step 3

3 | Replace the wiring harness side of the inflatable restraint steering wheel module yellow 2-way connector. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 16 | --
4 |

1. Reconnect the inflatable restraint steering wheel module yellow 2-way connector.
2. Make sure that the connector position assurance (CPA) is properly installed.
3. Turn the ignition switch to the ON position.
4. Use the scan tool to request the SIR DTC display.

Is DTC B1026 current?

--

Go to Step 5

Go to Diagnostic Aids

5 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint IP module yellow 2-way connector and the inflatable restraint steering wheel module yellow 2-way connector.
3. Install the J 38715-A SIR Driver/Passenger Load Tool to the wiring harness side of the inflatable restraint IP module yellow 2-way connector and the inflatable restraint steering wheel module yellow 2-way connector. Use the J 38715-25 adaptor for the inflatable restraint steering wheel module yellow 2-way connector and the J 38715-15 adaptor for the inflatable restraint IP module yellow 2-way connector.
4. Turn the ignition switch to the ON position.
5. Use the scan tool to request the SIR DTC display.

Is DTC B1026 current?

--

Go to Step 9

Go to Step 6

6 |

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 the J 38715-A from the inflatable restraint steering wheel module yellow 2-way connector.
4. Connect the inflatable restraint steering wheel module yellow 2-way connector.
5. Connect the J 38715-A to the upper inflatable restraint steering wheel module coil connector on the steering column. Use the J 38715-30 adaptor for the upper coil connector.
6. Turn the ignition switch to the RUN position.
7. Use the scan tool to request the SIR DTC display.

Is DTC B1026 current?

--

Go to Step 8

Go to Step 7

7 |

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 16

--

8 |

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 16

--

9 |

1. Turn the ignition switch to the OFF position.
2. Remove the J 38715-A .
3. Disconnect the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
4. Check for proper connections at terminal A6 and terminal A7 of the SDM wiring harness connector.

Is the SDM wiring harness connected properly?

--

Go to Step 11

Go to Step 10

10 | Replace the SDM wiring harness connector. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 16 | --
11 |

1. Zero the J 39200 Digital Multimeter (DMM).
2. Use the J 39200 to measure the resistance between terminal 2 of the inflatable restraint steering wheel module yellow 2-way connector and terminal A6 of the SDM wiring harness connector.

Is the measured resistance within the specified value?

0-0.5 ohms

Go to Step 13

Go to Step 12

12 | Locate and repair an open or a high resistance condition in the driver frontal high circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 16 | --
13 | Use the J 39200 to measure the resistance between terminal 1 of inline connector the inflatable restraint steering wheel module yellow 2-way connector and terminal A7 of the SDM wiring harness connector. Is the measured resistance within the specified value? | 0-0.5 ohms | Go to Step 15 | Go to Step 14
14 | Locate and repair an open or a high resistance condition in the driver frontal low circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 16 | --
15 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Is the repair complete? | -- | Go to Step 16 | --
16 |

1. Reconnect all SIR components.
2. Make sure that all components and connectors are properly mounted.
3. Turn the ignition switch to the ON position.
4. Use the scan tool to clear all current and history SIR DTCs.

Have all current and history SIR DTCs been cleared?

--

Go to SIR Diagnostic System Check

--