Chart B - Air Bag Warning Lamp Comes on Steady

CIRCUIT DESCRIPTION
When the ignition switch is turned On, "Ignition 1" voltage is applied to the AIR BAG telltale, Lamp Driver and SDM. The AIR BAG telltale is also connected to the SDM through the Lamp Driver module. When the ignition switch is turned from Off to On, the SDM flashes the AIR BAG telltale seven times. If there are no faults in the SIR system, the SDM will then turn off the AIR BAG telltale. The Lamp Driver module operates as the interface between the telltale and the SDM, switching circuit 358 to ground. Under normal operation circuit 358 is NOT GROUNDED and the AIR BAG telltale should be Off.

CHART TEST DESCRIPTION
The numbers below refer to the step numbers listed on the diagnostic chart.
Step 3. This step uses the scan tool to determine if the SDM is powered up and able to function.
Step 4. This step is a check of the ignition voltage as seen by the SDM.
Step 5. This step is a visual inspection of the SDM connector.
Step 7. This step checks for an open circuit 875.
Step 8. This step checks for a grounded circuit 875.
Step 10. This step checks for an open to see if the telltale is "On" because of the lamp driver module.
Step 12. This step checks for a short to ground in circuit 358.
Step 16. This step is a reminder to perform the Diagnostic System Check after completing all SIR system repairs.

DIAGNOSTIC AIDS
An inoperative SDM, open circuit 875, or open in circuit 39 to the lamp driver will turn on the AIR BAG telltale steady. If the AIR BAG telltale flashed seven times when turning ignition switch from Off to On, this chart will not be helpful.

Always perform the "SIR Diagnostic System Check" before using this chart. Diagnostic System Check

When measurements are requested in this chart, use SA 91114NE digital multimeter with correct terminal adapter from SA 92O6Z. When a check for proper connection is requested, refer to "Intermittent and Poor Connections." When a wire connector or terminal repair is requested, use the proper repair parts and refer to "Wiring Repair." Intermittents and Poor Connections

NOTICE: Perform "SIR DIAGNOSTIC SYSTEM CHECK" before proceeding with this chart.

NOTE: Air bag telltale will flash seven times and remain "On" after the same DTC appears twice. After a fault is detected twice the DTC is stored in memory as history code. If the air bag telltale is On, the DTC can he current or history code.