B1025

Circuit Description
When you first turn the ignition switch to the RUN position, the supplemental restraint sensing diagnostic module (SDM) performs tests to diagnose critical malfunctions within the SDM. Upon passing these tests, the following circuits are measured in order to ensure that they are within their respective normal voltage ranges:
- IGNITION 1
- 23 VLR
- Deployment loop voltages

The SDM monitors the voltages at DRIVER SIDE LOW terminal 3 and PASSENGER SIDE LOW terminal 4 to detect shorts to B+ in the inflator module circuits.

Conditions for Setting the DTC
- The voltage at PASSENGER SIDE LOW terminal 4 is less than 4.8 volts.
- The voltage at DRIVER SIDE LOW terminal 3 is more than 4.8 volts for 500 milliseconds.

The CONTINUOUS MONITORING test inspects for this DTC. This test occurs when IGNITION 1 is within the normal operating voltage range.

Action Taken When the DTC Sets
- The SDM sets a diagnostic trouble code.
- The SDM turns the AIR BAG warning lamp to the ON position.

Conditions for Clearing the DTC
- Current DTC- The voltage at DRIVER SIDE LOW terminal 3 is less than 4.8 volts for 500 milliseconds.
- History DTC
- You issue a scan tool CLEAR CODES command.
- After 250 malfunction free ignition cycles have occurred.

Diagnostic Aids
A short to B+ in the supplemental restraint steering wheel module circuit may cause an intermittent condition. Inspect CKT 347 and CKT 348 carefully for cutting or chafing. The diagnostic table directs the technician to note the entry value of DRIVER SENSELO. Comparing the value of DRIVER SENSELO may be helpful in determining if an intermittent condition exists.
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 an inspection 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.

Steps 1 - 2:

Step 3:

Steps 4 - 5:

Steps 6 - 8:

Steps 9 - 12:

Test Description
The numbers below refer to the step numbers on the diagnostic table:
2. This test determines the driver side low voltage which is measured by the supplemental restraint sensing and diagnostic module (SDM).
3. This test isolates the malfunction to one side of the supplemental restraint steering wheel module coil yellow 2-way connector.
4. This test determines whether the malfunction is due to the supplemental restraint steering wheel module or the module coil.
7. This test determines whether the malfunction is in CKT 347.
9. This test determines whether the malfunction is in CKT 348.