Circuit Description
When you first turn ON the ignition, 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 range. Then the SDM proceeds with the deployment loop continuity test. During the deployment loop continuity test, the SDM measures the voltage difference between the driver side high circuit and the driver side low circuit.
Conditions for Running the DTC
IGNITION 1 voltage is within the normal operating voltage range.
Conditions for Setting the DTC
| • | The voltage difference between the driver side high circuit and the driver side low circuit is more than or equal to 400 millivolts. |
| • | The malfunction must be present for at least 500 milliseconds. |
| • | If the malfunction is detected in this test, the resistance measurement test will not be performed. |
Action Taken When the DTC Sets
The SDM turns ON the AIR BAG warning lamp.
Conditions for Clearing the DTC
| • | The voltage difference between the driver side high circuit and the driver side low circuit is less than 400 millivolts for 500 milliseconds. |
| • | You can issue a CLEAR CODES command. |
| • | A history DTC will clear once 255 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 connector. |
| • | A poor connection at the upper inflatable restraint steering wheel coil connector. |
| • | An open in the driver side high circuit. |
| • | An open in the driver side low circuit. |
An intermittent open in the inflatable restraint steering wheel module coil could also set this DTC. To test for a bad inflatable restraint steering wheel module coil, clear the DTC's, then turn the steering wheel back and forth with the ignition ON. If the AIR BAG warning lamp comes ON and DTC B1026 has set again, it is likely the inflatable restraint steering wheel module coil is malfunctioning.
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
The numbers below refer to the step numbers on the diagnostic table:
-
This step checks the driver deployment loop voltage difference that was measured by the inflatable restraint sensing and diagnostic module (SDM).
-
This step checks to see if the inflatable restraint steering wheel module coil yellow 2-way wiring harness connector is corroded or damaged.
-
This step isolates the malfunction to one side of the inflatable restraint steering wheel module coil yellow 2-way wiring harness connector.
-
This step determines if there is a malfunctioning inflatable restraint steering wheel module coil or if there is a malfunctioning inflatable restraint steering wheel module.
-
This step checks the SDM wiring harness connector for corrosion or damaged terminals.
-
This step checks to see if there is an open in the driver side high circuit.
-
This step determines if there is an open in the driver side low circuit or if there is a malfunctioning SDM.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the SIR Diagnostic System Check? | -- | ||
Has the DRIVER VDIF been read and recorded on the repair order? | -- | -- | ||
Are the terminals damaged or corroded? | -- | |||
4 | Replace the inflatable restraint steering wheel module coil yellow 2-way wiring harness connector. Refer to Connector Repairs . Did you complete the repair? | -- | -- | |
5 | Check for a proper connection of the driver side high circuit and the driver side low circuit at the inflatable restraint steering wheel module coil yellow 2-way connector. Are the terminals damaged or corroded? | -- | ||
6 | Check for a proper connection of the driver side high circuit and the driver side low circuit at the inflatable restraint steering wheel module coil yellow 2-way connector. Are the terminals damaged or corroded? | -- | ||
7 | Replace the inflatable restraint steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement . Did you complete the repair? | -- | -- | |
8 |
Is DRIVER VDIF less than the specified value? | 400 mV | ||
9 |
Did you complete the repair? | -- | -- | |
Is DRIVER VDIF less than the specified value? | 400 mV | |||
Is DRIVER VDIF less than the specified value? | 400 mV | |||
12 |
Did you complete the repair? | -- | -- | |
13 |
Did you complete the repair? | -- | -- | |
Is the SDM wiring harness connector damaged or corroded? | -- | |||
15 | Replace the SDM wiring harness connector. Refer to Connector Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
16 | Check for a proper connection of the driver side high circuit and the driver side low circuit at the SDM. Are the SDM terminals damaged or corroded? | -- | ||
17 | Check for a proper connection of the driver side high circuit and the driver side low circuit at the SDM. Are the SDM terminals damaged or corroded? | -- | ||
18 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the repair? | -- | -- | |
Is the measured resistance within the specified value? | 0-0.5 ohms | |||
20 |
Did you complete the repair? | -- | -- | |
Use the J 39200 to measure the resistance of the driver side low circuit between the SDM wiring harness connector and the inflatable restraint steering wheel module coil yellow 2-way wiring harness connector. Is the measured resistance within the specified value? | 0-0.5 ohms | |||
22 |
Did you complete the repair? | -- | -- | |
23 |
Did you complete the action? | -- | -- |
