B1901

DTC B1901

CIRCUIT DESCRIPTION
The seat belt pretensioner deployment loop consists of a seat belt pretensioner, the seat belt pretensioner - high and seat belt pretensioner - low circuits. A shorting bar is used in the seat belt pretensioner connector which will short together the seat belt pretensioner - high and seat belt pretensioner - low circuits when the connector is disconnected, this will help to prevent unwanted deployment of the pretensioner during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (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 B1900 Driver Pretensioner Deployment Loop Resistance Too Low
- DTC B1901 Driver Pretensioner Deployment Loop Resistance Too High
- DTC B1902 Driver Pretensioner Deployment Loop Short To Ground
- DTC B1903 Driver Pretensioner Deployment Loop Short To Voltage

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

CONDITIONS FOR SETTING THE DTC
- DTC B1900 will set when the SDM detects a low resistance condition in the seat belt pretensioner - LF deployment loop.
- DTC B1901 will set when the SDM detects a high resistance condition in the seat belt pretensioner - LF deployment loop.
- DTC B1902 will set when the SDM detects a short to ground in the seat belt pretensioner - LF deployment loop.
- DTC B1903 will set when the SDM detects a short to voltage in the seat belt pretensioner - LF deployment loop.

ACTION TAKEN WHEN THE DTC SETS
The SDM commands the AIR BAG indicator to flash.

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 seat belt pretensioner - left - high and the seat belt pretensioner - left - low circuits
- An open or high resistance in seat belt pretensioner - left - high or the seat belt pretensioner - left - low circuits
- A short to ground in the seat belt pretensioner - left - high or the seat belt pretensioner - left - low circuits
- A short to voltage in the seat belt pretensioner - left - high or the seat belt pretensioner - left - low circuits
- A malfunctioning seat belt pretensioner
- 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 - 13:

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 seat belt pretensioner.
8. This step tests to see if the malfunction is caused by the seat belt pretensioner.
10. If DTC B1900 is present, test for a short between the seat belt pretensioner - left - high and the seat belt pretensioner - left - low circuits.If DTC B1901 is present, test the seat belt pretensioner - left - high and the seat belt pretensioner - left - low circuits for an open or high resistance.If DTC B1902 is present, test the seat belt pretensioner - left - high and the seat belt pretensioner - left - low circuits for a short to ground.If DTC B1903 is present, test the seat belt pretensioner - left - high and the seat belt pretensioner - left - low circuits for a short to voltage.