B1147

Circuit Description
When you turn the ignition switch to the RUN position, the Inflatable Restraint Side Impact Sensing Module (SISM) performs tests to diagnose critical malfunctions within the module. The SISM then tests for the following conditions:
^ Deployment loop open
^ Deployment loop short to ground
^ Deployment loop short to ignition
^ Deployment loop resistance high
^ Deployment loop resistance low
^ Deployment reserve energy failure.

The Inflatable Restraint side impact sensing module (SISM) transmits a pulse width modulated signal to the Inflatable Restraint Sensing and Diagnostic Module (SDM) over circuit 2107. A 300 millisecond pulse width with a 50 % duty cycle is the normal mode. This mode indicates that the SISM is operating normally and no faults exist. The SISM communicates a turning OFF mode (ignition OFF) by sending a 20 millisecond pulse width modulated signal with a 50 % duty cycle.

Conditions for Setting the DTC
The SDM receives a pulse width signal other than the normal signal, or no signal at all. The SISM performs tests during POWER-ON tests, CONTINUOUS MONITORING tests, and Asynchronously.

Action Taken When the DTC Sets
^ The SDM sets DTC B1147.
^ The SDM commands the instrument panel cluster (IPC) in order to turn ON the AIR BAG warning lamp.

Conditions for Clearing the DTC
^ Current DTC:
- The SDM receives a normal signal from the SISM.
- The ignition switch is cycled.
^ History DTC:
- You issue a scan tool CLEAR CODES command.
- 250 malfunction-free ignition cycles occur.

If a side impact deployment occurs the SISM must be replaced. Follow the instructions in the diagnostic table.

Diagnostic Aids
A poor connection can cause an intermittent condition.

Inspect the following components for a poor connection:
^ The SISM
^ The Inflatable Restraint side impact inflator module
^ The SDM terminal 13
^ The wire to terminal connections of all the circuits going to the SISM

If you suspect that the SISM may be the cause of the malfunction, you may switch the SISMs in order to verify an internal SISM malfunction.
When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616-A Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections. When a wire, connector or terminal repair is requested, use J 38125-B Terminal Repair Kit and refer to Wiring Repair. Intermittents and Poor Connections

Test Description
The numbers below refer to step numbers on the diagnostic table.
2. If the driver Inflatable Restraint side impact inflator deployed, DTC B1147 will set.
3. Components require inspection and possibly replacement after a side impact accident, whether deployment occurred or not.
9. This test determines it the malfunction is in the Inflatable Restraint side impact inflator module.
15. This test checks for an open in circuit 1751.
17. This test checks for an open in circuit 1139.
19. This test checks for a short-to-ground in circuit 2106.
21. This test checks for an open in circuit 2106.
23. This test checks for a short-to-voltage in circuit 2106.
25. This test checks for a short-to-voltage in circuit 2105.
27. This test checks for a short-to-voltage in circuit 2105.
29. This test checks for high resistance or open in circuit 2105.
31. This test checks for a short-to-ground in circuit 2107.
33. This test checks for a short to voltage in circuit 2107.
39. This test checks for an open in circuit 2107.
41. If all wiring and connections are OK, then and only then should the Inflatable Restraint Side Impact Sensing Module (SISM) be replaced.