B1901

DTC B1900, B1901, B1902, or B1903

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptors
DTC B1900
- Right Pretensioner Deployment Loop Resistance Too Low

DTC B1901
- Right Pretensioner Deployment Loop Resistance Too High

DTC B1902
- Right Pretensioner Deployment Loop Short to Ground

DTC B1903
- Right Pretensioner Deployment Loop Short to Voltage

Circuit/System Description

During a side or frontal crash of sufficient force the inflatable restraint sensing and diagnostic module (SDM) will allow current to flow through the deployment loop in order to deploy an inflatable restraint module. There are 2 shorting bars used within the module connector which will short together both high and low circuits, when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B1900

The inflatable restraint module deployment loop resistance is low 5 times during primary check.

B1901

The inflatable restraint module high and/or low circuit is open for 2 seconds.

B1902

The inflatable restraint module high and/or low circuit is short to ground for 500 milliseconds.

B1903

The inflatable restraint module high and/or low circuit is short to voltage for 500 milliseconds.

Action Taken When the DTC Sets

* The SDM commands the AIR BAG indicator ON.
* The SDM will store a DTC, however if an event occurs system will still attempt deployments.

Conditions for Clearing the DTC

* The condition for setting the DTC no longer exists.
* A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Reference Information
Schematic Reference

SIR Schematics ([1][2]Air Bag Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

SIR System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
* Connector Repairs (Connector Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

Each inflatable restraint module requires a specific adapter to connect the load tool to the SIR system.

* J 38715-A Driver and Passenger SIR Load Tool
* J 38715-XX Load Tool Adaptor

Circuit/System Testing

Note: Refer to SIR Service Precautions (Technician Safety Information).

When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.

* The pretensioner
* The inflatable restraint module
* The SDM module
* The inflatable restraint module wiring harness connector
* The SDM wiring harness connector

1. Ignition OFF, disconnect the harness connector at the appropriate inflatable restraint module.
2. With the appropriate adaptor, connect J 38715-A or SA9409Z-A in place of the inflatable restraint module.
3. Ignition ON, with a scan tool, verify the appropriate DTC is set as current.

• If the DTC is not set or is set as history, replace the appropriate inflatable restraint module.

4. Ignition OFF, disconnect J 38715-A or SA9409Z-A and the appropriate adaptor.
5. Disconnect the harness connector at the SDM.
6. Ignition ON, test for less than 1 volt between right seatbelt pretensioner terminal 1 and ground.

• If not within the specified range, test the circuit for a short to voltage.

7. Test for less than 1 volt between right seatbelt pretensioner terminal 2 and ground.

• If not within the specified range, test the circuit for a short to voltage.

8. Ignition OFF, test for infinite resistance between right seatbelt pretensioner terminal 1 and ground.

• If not within the specified range, test the circuit for a short to ground.

9. Test for infinite resistance between right seatbelt pretensioner terminal 2 and ground.

• If not within the specified range, test the circuit for a short to ground.

10. Test for less then 1 ohm between right seatbelt pretensioner terminal 1 and SDM terminal 4.

• If not within the specified range, test the circuit for an open/high resistance.

11. Test for less then 1 ohm between right seatbelt pretensioner terminal 2 and SDM terminal 5.

• If not within the specified range, test the circuit for an open/high resistance.

12. If all circuits test normal, replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Instrument Panel Inflatable Restraint Module Replacement (Instrument Panel Inflatable Restraint Module Replacement)
* Roof Side Rail Inflatable Restraint Module Replacement (Roof Side Rail Inflatable Restraint Module Replacement)
* Seat Belt Retractor Pretensioner Replacement - Left Front (Seat Belt Retractor Pretensioner Replacement - Left Front)
* Seat Belt Retractor Pretensioner Replacement - Right Front (Seat Belt Retractor Pretensioner Replacement - Right Front)
* SIR/SRS Wiring Repairs (SIR/SRS Wiring Repairs)
* Control Module References (Programming and Relearning) for SDM replacement, setup, and programming