B1812

DTC B1812

CIRCUIT DESCRIPTION
The steering wheel module deployment loop consists of a dual stage inflatable restraint steering wheel module, an inflatable restraint steering wheel module coil, the steering wheel module - high and steering wheel module - low circuits. There are 2 shorting bar 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.

DTC DESCRIPTORS
This diagnostic procedure supports the following DTCs:
- DTC B1810 Driver Air Bag Deployment Loop Resistance Too Low Circuit 2
- DTC B1811 Driver Air Bag Deployment Loop Resistance Too High Circuit 2
- DTC B1812 Driver Air Bag Deployment Loop Short To Ground Circuit 2
- DTC B1813 Driver Air Bag Deployment Loop Short To Battery Circuit 2

CONDITIONS FOR RUNNING THE DTC
Ignition 1 voltage is within the normal operating voltage range.

CONDITIONS FOR SETTING THE DTC
- DTC B1810 will set when the SDM detects a low resistance condition in the steering wheel module deployment loop.
- DTC B1811 will set when the SDM detects a high resistance condition in the steering wheel module deployment loop.
- DTC B1812 will set when the SDM detects a short to ground in the steering wheel module deployment loop.
- DTC B1813 will set when the SDM detects a short to voltage 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 between the steering wheel module - high and the steering wheel module - low circuits
- An open or high resistance 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
- A short to voltage in the steering wheel module - high or 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 Diagnostic Aids for Circuit Testing and Wiring Repair procedures.

TEST DESCRIPTION

Steps 1 - 11:

Steps 12 - 16:

The numbers below refer to the step numbers on the diagnostic table.
7. 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.
10. This step tests to see if the malfunction is caused by the inflatable restraint steering wheel module coil.
12. This step tests for a short between the steering wheel module high and steering wheel module low circuits.