Circuit Description
When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within the SIR system. The SDM monitors the instrument panel (I/P) module disable switch - signal and I/P module disable switch indicator - control circuits in order to determine whether or not to disable the inflatable restraint I/P module. The SDM also monitors the I/P module disable switch - signal and the I/P module disable switch indicator - control circuits for an open, high resistance, short to ground or short to voltage condition.
DTC Descriptors
This diagnostic procedure supports the following DTC:
DTC B0091 Active Switch Wrong State
Conditions for Running the DTC
Ignition 1 voltage is within the normal operating voltage range.
Conditions for Setting the DTC
| • | The PSIR switch must be in the OFF position. |
| • | The voltage detected in the I/P module disable switch - signal circuit is less than 1 volt. |
| • | The voltage detected in the I/P module disable switch indicator - control circuit is greater than 1 volt. |
Action Taken When the DTC Sets
| • | The SDM defaults to the OFF position, disabling the I/P module. |
| • | The SDM attempts to turn the inflatable restraint I/P module disable switch indicator ON and OFF every 5 seconds. |
| • | The SDM commands the AIR BAG indicator ON via Class 2 serial data. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used. |
| • | A history DTC will clear once 255 malfunction free ignition cycles have occurred. |
Diagnostic Aids
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in misdiagnosis, causing a part replacement with the reappearance of the malfunction.
The following are possible causes of the malfunction:
| • | An open or a high resistance in the I/P module disable switch - signal circuit |
| • | An open or a high resistance in the I/P module disable switch indicator - control circuit |
| • | A short between the I/P module disable switch-signal and I/P module disable switch indicator - control circuits |
| • | Damage or corrosion on the I/P module disable switch harness connector |
| • | Damage or corrosion on the I/P module disable switch indicator harness connector |
| • | Damage or corrosion on the SDM harness connector |
| • | An internal I/P module disable switch malfunction |
| • | An internal I/P module disable switch indicator malfunction |
| • | An internal SDM malfunction |
If an intermittent condition exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
This step tests to see if the I/P module disable switch indicator is damaged.
-
This step tests to see if there is an open or high resistance in the I/P module disable switch-signal circuit.
-
This step tests to see if there is an open or high resistance in the I/P module disable switch indicator-control circuit.
-
This step test to see if there is a short between the I/P module disable switch-signal and the I/P module disable switch indicator-control circuits.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Did you find and correct the condition? | Go to Step 15 | Go to Step 3 |
3 | Inspect the I/P module disable switch terminals for damage or corrosion that may cause the malfunction. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Does the I/P module disable switch terminals exhibit signs of damage or corrosion? | Go to Step 12 | Go to Step 4 |
4 |
Did you find and correct the condition? | Go to Step 15 | Go to Step 5 |
5 | Inspect the I/P module disable switch indicator connector for damage or corrosion that may cause the malfunction. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 6 |
Test the I/P module disable switch indicator for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 7 | |
7 |
Did you find and correct the condition? | Go to Step 15 | Go to Step 8 |
8 | Inspect the SDM terminals for damage or corrosion that may cause the malfunction. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Do the SDM terminals exhibit signs of damage or corrosion? | Go to Step 14 | Go to Step 9 |
Test the I/P module disable switch - signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 10 | |
Test the I/P module disable switch indicator - control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 11 | |
Test the I/P module disable switch - signal circuit and the I/P module disable switch indicator - control circuit for a short between the two circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | -- | |
12 | Replace the I/P module disable switch. Refer to Inflatable Restraint Instrument Panel Module Disable Switch Replacement . Did you complete the replacement? | Go to Step 13 | -- |
13 |
Does the DTC reset? | Go to Step 14 | System OK |
14 | Replace the SDM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 15 | -- |
15 |
Does the DTC reset? | Go to Step 2 | System OK |
