DTC 0021

DTC 0021

CIRCUIT DESCRIPTION
The steering wheel module deployment loop consists of an 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 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.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTCs:
DTC 0021 Driver Deployment Loop Resistance High
DTC 0022 Driver Deployment Loop Resistance Low

CONDITIONS FOR RUNNING THE DTC
Ignition Voltage is within the normal operating voltage range.

CONDITIONS FOR SETTING THE DTC
- DTC 0021 will set when the SDM detects a high resistance condition in the steering wheel module deployment loop.
- DTC 0022 will set when the SDM detects a low resistance condition 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:
- An open or high resistance in the steering wheel module high or the steering wheel module low circuits
- A short between the steering wheel module high and the steering wheel module low circuits
- A malfunctioning inflatable restraint steering wheel module
- A malfunctioning inflatable restraint steering wheel module coil
- An internal SDM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections.

TEST DESCRIPTION

Step 1 - Step 12:

Step 13 - Step 15:

The numbers below refer to the step numbers on the diagnostic table.
5. This step tests to see if the malfunction is caused by the inflatable restraint steering wheel module.
8. This step tests to see if the malfunction is caused by the inflatable restraint steering wheel module coil.
9. This step tests to see if the malfunction is caused by the inflatable restraint steering wheel module coil.
11. If DTC 0021 is present, test the steering wheel module high and the steering wheel module low circuits for an open or high resistance.If DTC 0022 is present, test for a short between the steering wheel module high and the steering Wheel Module Low circuits.