Circuit Description
The driver frontal deployment loop consists of the following components:
| • | A dual stage inflatable restraint steering wheel module |
| • | The inflatable restraint steering wheel module coil |
| • | The steering wheel module high circuits for both stages 1 and 2 |
| • | The steering wheel module low circuits for both stages 1 and 2 |
There are 2 shorting bars used within the steering wheel module coil connector which will short together both steering wheel module stage 1 high circuit and steering wheel module stage 1 low circuit and both steering wheel module stage 2 high circuit and steering wheel module stage 2 low circuit when the connector is disconnected, this will help 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) will allow current to flow through the deployment loop in order to deploy the steering wheel module. 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 DTC will be stored in memory.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B0022 Driver Frontal Deployment Loop stage 1 Resistance Low |
| • | DTC B0024 Driver Frontal Deployment Loop stage 1 Voltage Out of Range |
| • | DTC B0026 Driver Frontal Deployment Loop stage 1 Open |
| • | DTC B0042 Driver Frontal Deployment Loop stage 2 Resistance Low |
| • | DTC B0043 Driver Frontal Deployment Loop stage 2 Voltage Out of Range |
| • | DTC B0044 Driver Frontal Deployment Loop stage 2 Open |
Conditions for Running the DTC
Ignition 1 voltage is within the normal operating voltage range.
Conditions for Setting the DTC
| • | DTC B0022 - stage 1 or B0042 - stage 2 will set when the steering wheel module deployment loop resistance is less than 1.3 ohms for 500 milliseconds. |
| • | DTC B0024 - stage 1 or B0043 - stage 2 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 500 milliseconds. |
| - | Steering wheel module high circuit is less than 2.4 volts and steering wheel module deployment loop resistance is less than 6 ohms for 500 milliseconds. |
| • | DTC B0026 - stage 1 or B0044 - stage 2 will set when one of the following conditions occurs: |
| - | Steering wheel module high circuit is less than 2.4 volts and the steering wheel module deployment loop is more than 6 ohms for 500 milliseconds. |
| - | Steering wheel module deployment loop resistance is more than 4.8 ohms for 500 milliseconds. |
Action Taken When the DTC Sets
The SDM commands the AIR BAG indicator ON via class 2 serial data.
Conditions for Clearing the DTC
| • | 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. |
Diagnostic Aids
The following are possible causes of the malfunction:
| • | A short between the steering wheel module stage 1 or stage 2, high and low circuits. |
| • | An open or a high resistance in the steering wheel module stage 1 or stage 2, high or low circuits. |
| • | A short to ground or a short to voltage in the steering wheel module stage 1 or stage 2, 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 .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests to see if the malfunction is caused by the steering wheel module or by the steering wheel module coil.
-
This step tests to see what DTCs are present. If DTC B0022 or B0042 is present, test for a short between the steering wheel module high and low circuits in stage 1 or stage 2. If DTC B0024 or B0043 is present, test the steering wheel module high and low circuits for an open and for high resistance in stage 1 or stage 2. If DTC B0026 or B0044 is present, test the steering wheel module high and low circuits for an open and for high resistance in stage 1 or stage 2.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | 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 |
Important: When installing SA9409Z-A SIR Driver/Passenger Load Tool for testing the dual stage steering wheel module, the correct 4-way load tool adapter connector must be used. Failure to use the correct 4-way load tool connector will set additional codes when testing. Does the scan tool indicate that DTC B0022, B0024, B0026, B0042, B0043, or B0044 are current? | Go to Step 6 | Go to Step 5 |
Does the scan tool indicate that DTC B0022, B0024, B0026, B0042, B0043, or B0044 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 |
Important: If scan tool display multiple codes diagnose the open code first. 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 |
