The inflatable restraint steering wheel module deployment loop consists of the inflatable restraint steering wheel module, the inflatable restraint steering wheel module coil, and the steering wheel module high and low circuits. A shorting bar used within the steering wheel module coil connector shorts together the steering wheel module high and low circuit when the connector is disconnected. This helps to prevent unwanted deployment of the inflator module during servicing. During a frontal crash of sufficient force the inflatable restraint sensing and diagnostic module (SDM) allows current to flow through the deployment loop in order to deploy the steering wheel module. When the ignition is turned ON, the SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a diagnostic trouble code (DTC) will be stored in memory.
Ignition 1 voltage is within the normal operating voltage range.
• | DTC B0022 will set when the steering wheel module deployment loop resistance is less than 1.3 ohms for 300 milliseconds. |
• | DTC B0024 will set when one of the following conditions occur: |
• | Steering wheel module high and/or low circuits is short to ground or short to voltage for 300 milliseconds. |
• | Steering wheel module high circuit is less than 2 volts and steering wheel module deployment loop resistance is less than 6 ohms for 300 milliseconds. |
• | DTC B0026 will set when one of the following conditions occurs: |
- | Steering wheel module high circuit is less than 2 volts and the steering wheel module deployment loop resistance is more than 4.8 ohms for 500 milliseconds. |
- | Steering wheel module deployment loop resistance is more than 6 ohms for 300 milliseconds. |
The SDM commands the AIR BAG indicator ON via Class 2 serial data.
• | The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used. |
• | A history DTC will clear once 255 malfunction free ignition cycles have occurred. |
The following are possible causes of the malfunction:
• | A short between the steering wheel module high and low circuits. |
• | An open or a high resistance in the steering wheel module high or low circuits. |
• | A short to ground or a short to voltage in the steering wheel module high or low circuits. |
• | The steering wheel module coil connector |
• | The SDM connector |
• | A malfunctioning steering wheel module |
• | A malfunctioning steering wheel module coil |
• | A malfunctioning SDM |
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
The numbers below refer to the step numbers on the diagnostic table.
Tests to see if the malfunction is caused by the steering wheel module or by the steering wheel module coil.
Tests to see what DTCs are present. If DTC B0022 is present, test the steering wheel module for a short between high and low circuits. If DTC B0024 is present, test the steering wheel module high and low circuits for an open and for high resistance. If DTC B0026 is present, test the steering wheel module high and low circuits for an open and for high resistance.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: SIR Schematics | |||
1 | Did you perform the Diagnostic System Check - SIR? | Go to Step 2 | |
2 |
Does the connector exhibit any signs of damage or corrosion? | Go to Step 3 | Go to Step 4 |
3 |
Did you complete the repair? | Go to Step 11 | -- |
4 |
Does the scan tool indicate that DTC B0022, B0024, or B0026 are current? | Go to Step 6 | Go to Step 5 |
Does the scan tool indicate that DTC B0022, B0024, or B0026 are current? | Go to Step 9 | Go to Step 8 | |
6 |
Did you find and correct the condition? | Go to Step 11 | Go to Step 7 |
Did you find and correct the condition? | Go to Step 11 | Go to Step 10 | |
8 |
Did you complete the replacement? | Go to Step 11 | -- |
9 |
Did you complete the replacement? | Go to Step 11 | -- |
10 |
Did you complete the replacement? | Go to Step 11 | -- |
11 |
Does the DTC reset? | Go to Step 2 | System OK |