B0090

Circuit Description
When you first turn the ignition switch to the RUN position, the supplemental restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM monitors the voltage levels at the passenger frontal SRS enable and disable terminals of the SDM to determine the position of the supplemental restraint IP module switch. The SDM then performs the following continuous diagnostic tests on the deployment loops:
- Deployment loop voltage out of range test
- Deployment loop resistance measurement test

If the voltage out of range test detects a short to voltage condition, the resistance measurement test for that deployment loop will not be performed.

Conditions for Running the DTC
- Ignition 1 voltage is within the normal operating voltage range.
- Passenger frontal deployment loop is not shorted to voltage.

Conditions for Setting the DTC
- The voltage detected at passenger frontal SRS enable terminal and passenger frontal SRS disable terminal are less than 1.0 volt when the AIR BAG ON lamp is commanded ON.
- The voltage detected at passenger frontal SRS enable terminal and passenger frontal SRS disable terminal are greater than 4.0 volts when the AIR BAG ON lamp is commanded OFF.
- The voltage detected at passenger frontal SRS enable terminal and passenger frontal SRS disable terminal are greater than 1.0 volt when the AIR BAG OFF lamp is commanded ON.

Action Taken When the DTC Sets
- The supplemental restraint IP module switch is defaulted to the disabled state.
- The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.
- The SDM attempts to illuminate the supplemental restraint IP module switch AIR BAG OFF lamp.

Conditions for Clearing the DTC
- The supplemental restraint IP module switch AIR BAG lamp is OFF, and the voltage at passenger frontal SRS enable terminal and passenger frontal SRS disable terminal are in opposite states for 300 milliseconds.
- You issue a scan tool CLEAR CODES command.
- A history DTC will clear once 255 malfunction free ignition cycles have occurred.

When the SDM detects that no DTCs are present, the SDM commands the AIR BAG warning lamp OFF.

Diagnostic Aids
The following can cause an intermittent condition:
- A short between the the passenger frontal SRS enable and the passenger frontal SRS disable circuits.
- Refer to Testing for Intermittent and Poor Connections in Wiring Systems.

Steps 1 - 2:

Steps 3 - 5:

Steps 6 - 9:

Steps 10 - 12:

Steps 13 - 15:

Steps 16 - 18:

Steps 19 - 21:

Steps 22 - 24:

Steps 25 - 29:

Steps 30 - 33:

Test Description
The numbers below refer to the step numbers on the diagnostic table:

2. Test determines if the AIR BAG ON lamp illuminates when the supplemental restraint IP module switch is in the ON position.
3. Tests for a poor connection at the supplemental restraint IP module switch harness connector.
6. Test determines whether the malfunction is in the supplemental restraint IP module switch ground circuit.
8. Test determines whether the malfunction is in the power feed circuit between the fuse block and the supplemental restraint IP module switch.
11. Tests for proper contact or corrosion of the supplemental restraint sensing and diagnostic module (SDM) harness connector.
12. Tests for an open or high resistance in the passenger SRS enable circuit.
14. Tests for a short to ground in the passenger SRS enable circuit.
16. Tests for a short to voltage in the passenger SRS disable circuit.
18. Tests for a short between the passenger SRS enable and disable circuits.
24. Tests for a short to voltage in the passenger SRS disable circuit.
26. Tests for a short to voltage in the passenger SRS enable circuit.
28. Tests for an open or high resistance in the passenger SRS disable circuit.
30. Tests for a short to ground in the passenger SRS disable circuit.