R024

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

During normal non-deployment operation of the SIR system, a small amount of current flows through both the driver's and passenger's deployment loops. The diagnostic resistors within the Dual Pole Arming Sensor and the Discriminating sensors along with the resistance of the Inflator Modules, cause voltage drops within the deployment loops. The DERM monitors the voltage at 'DRIVER'S SENSE LOW', terminal 'B8', and 'PASSENGER'S SENSE LOW', terminal 'B7', to detect shorts or opens within the deployment loops. When the measured voltage at terminals 'B8' or 'B7' is below 39% of its respective 36 VLR for 500 milliseconds, Code R024 is set.

TEST CONDITION(S)

Tested every 100 milliseconds while 'Continuous Monitoring' tests active.

FAILURE CONDITION(S)

Voltage at the 'DRIVER'S SENSE LOW', terminal 'B8', or 'PASSENGER'S SENSE LOW', terminal 'B7', is less than 39% of its respective 36 VLR, terminals A3' or A4', for 500 milliseconds.

ACTION TAKEN

1. DERM turns on the 'INFLATABLE RESTRAINT' indicator.

2. 'SERVICE SUPPLEMENTAL INFLATABLE RESTRAINT' message is displayed on DIC.

NOTES ON FAULT TREE

1. If greater than 31 volts is measured, the fault is not due to the high side of the Driver's Initiator circuit.

2. If greater than 31 volts is measured the fault is not due to the high side of the Passenger's Initiator circuit.

3. Checking CKT 1403 for an open between C231 and Dual Pole Arming Sensor.

4. Checking if high resistance in CKT 1401 is causing the voltage to below 31 volts.

5. Checking CKT 1403 for a short to ground. If OK, the Dual Pole Arming Sensor is shorted internally causing the voltage drop.

6. Checking CKT 347 for an open between C206 and Dual Pole Arming Sensor.

7. Checking if high resistance in CKT 236 is causing the voltage to be below 31 volts.

8. Checking CKT 347 for a short to ground. If OK, the Dual Pole Arming Sensor is shorted internally causing the voltage drop.

9. Checking for a partial short across the diagnostic resistor in the Forward Discriminating sensor.

10. Checking Forward Discriminating sensor for a short to ground.

11. Checking for a shorted LH Discriminating sensor.

12. Checking for a LH Discriminating sensor shorted to ground.

13. Checking for CKT 349 shorted to ground between Forward and LH Discriminating sensors.

14. Checking for CKT 349 shorted to ground between LH and RH Discriminating sensors.

15. Checking for a partial short across the diagnostic resistor in the RH Discriminating sensor.

16. Checking RH Discriminating sensor for a short to ground.

17. Checking CKT 348 to C206 for a short to ground.

18. Checking CKT 1404 to C231 for a short to ground.