Circuit Description
The steering wheel module deployment loop consists of a inflatable restraint steering wheel module, an inflatable restraint steering wheel module coil, the steering wheel module high and steering wheel module low circuits. A shorting bar is used in the inflatable restraint steering wheel module and the inflatable restraint steering wheel module coil connectors which will short together the steering wheel module high and steering wheel module low circuits 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 sensing and diagnostic module (SDM) will allow current to flow through the deployment loop in order to deploy the inflatable restraint 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.
Conditions for Running the DTC
Ignition voltage is within the normal operating voltage range.
Conditions for Setting the DTC
| • | DTC 17 will set when the SDM detects a short to voltage in the steering wheel module deployment loop. |
| • | DTC 18 will set when the SDM detects a short to ground in the steering wheel module deployment loop. |
Action Taken When the DTC Sets
The SDM commands the AIR BAG indicator ON.
Conditions for Clearing the DTC
The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
Diagnostic Aids
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.
The following are possible causes of the malfunction:
| • | A short to voltage in the steering wheel module high or the steering wheel module low circuits |
| • | A short to ground in the steering wheel module high or the steering wheel module low circuits |
| • | An internal SDM malfunction |
If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Test the steering wheel module high and the steering wheel module low circuits for a short to voltage.
-
Test to see if the malfunction is caused by the inflatable restraint steering wheel module.
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Test the steering wheel module high and the steering wheel module low circuits for a short to ground.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | ||||
1 | Did you perform A Diagnostic System Check - SIR? | -- | Go to Step 2 | |
2 | Is DTC 17 or 18 set as a current DTC? | -- | Go to Step 3 | Go to Diagnostic Aids |
3 | Is DTC 17 set as a current DTC? | -- | Go to Step 4 | Go to Step 5 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 | |
5 | Is DTC 18 set as a current DTC? | -- | Go to Step 6 | -- |
6 | Use the scan tool to display the driver's deployment loop resistance. Does the resistance display within the specified range? | Approximately 2.0-6.4 ohms | Go to Step 7 | Go to Step 8 |
7 |
Did the DTC status change from NO DTCs? | -- | Go to Step 10 | Go to Step 13 |
Does the resistance display as specified? | Approximately 3.0 ohms | Go to Step 11 | Go to Step 9 | |
Test the steering wheel module high and the steering wheel module low circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 | |
10 | Locate and repair an intermittent short to ground in the wiring harness. Refer to Testing for Intermittent Conditions and Poor Connections , Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | -- |
11 | Replace the steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
12 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
13 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
