Circuit Description
The driver frontal deployment loop consists of the dual stage inflatable restraint steering wheel module, the inflatable restraint steering wheel module coil, and the steering wheel module high and low circuits for both stages 1 and 2. Two shorting bars used within the steering wheel module coil connector short together both the steering wheel module stage 1 high and low circuits, and the steering wheel module stage 2 high and low circuits 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.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B0022 Left Front/Driver Frontal Deployment Loop (Single Stage or Stage 1) Resistance Low |
| • | DTC B0024 Left Front/Driver Frontal Deployment Loop (Single Stage or Stage 1) Voltage Out of Range |
| • | DTC B0026 Left Front/Driver Frontal Deployment Loop (Single Stage or Stage 1) Open |
| • | DTC B0042 Left Front/Driver Frontal Deployment Loop (Stage 2) Resistance Low |
| • | DTC B0043 Left Front/Driver Frontal Deployment Loop (Stage 2) Voltage Out of Range |
| • | DTC B0044 Left Front/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 in stage 1 or B0042 in stage 2 will set when the steering wheel module deployment loop resistance is less than 1.3 ohms for 500 milliseconds. |
| • | DTC B0024 in stage 1 or B0043 in 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 in stage 1 or B0044 in 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.
-
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 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: If the scan tool displays multiple codes, diagnose the open code first.
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 |
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 |
