Circuit Description
When you first turn the ignition switch to the RUN position, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM monitors the voltage levels at the passenger frontal SIR enable and disable terminals of the SDM to determine the position of the inflatable 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 SIR enable terminal and passenger frontal SIR disable terminal are less than 1.0 volt when the AIR BAG ON lamp is commanded ON. |
| • | The voltage detected at passenger frontal SIR enable terminal and passenger frontal SIR disable terminal are greater than 4.0 volts when the AIR BAG ON lamp is commanded OFF. |
| • | The voltage detected at passenger frontal SIR enable terminal and passenger frontal SIR disable terminal are greater than 1.0 volt when the AIR BAG OFF lamp is commanded ON. |
Action Taken When the DTC Sets
| • | The inflatable 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 inflatable restraint IP module switch AIR BAG OFF lamp. |
Conditions for Clearing the DTC
| • | The inflatable restraint IP module switch AIR BAG lamp is OFF, and the voltage at passenger frontal SIR enable terminal and passenger frontal SIR 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 SIR enable and the passenger frontal SIR disable circuits. |
| • | Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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Observes the state of the inflatable restraint IP module Switch, normal state being OFF.
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Tests for a malfunctioning inflatable restraint IP module switch.
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Tests for a malfunctioning inflatable restraint sensing and diagnostic module (SDM).
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Tests for a short in the signal circuits between the inflatable restraint IP module switch and the inflatable restraint sensing and diagnostic module (SDM).
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This step replaces the inflatable restraint sensing and diagnostic module (SDM).
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the SIR Diagnostic System Check? | -- | Go to Step 2 | |
Does the scan tool indicate that the inflatable restraint IP module switch is OFF? | -- | Go to Step 3 | Go to Step 4 | |
Does the inflatable restraint IP module switch data parameter change state? | -- | Go to Diagnostic Aids | Go to Step 4 | |
Does the scan tool indicate that the inflatable restraint IP module switch is OFF? | -- | Go to Step 7 | Go to Step 5 | |
Test the passenger SIR enable and disable circuits of the inflatable restraint IP module switch between the IP module switch and the SDM for a short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 | |
6 | Inspect for poor connections at the harness connector of the inflatable restraint sensing and diagnostic module (SDM). 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 10 | Go to Step 8 |
7 | Inspect for poor connections at the harness connector of the inflatable restraint IP module switch. 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 10 | Go to Step 9 |
Replace the inflatable restraint sensing and diagnsotic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- | |
9 | Replace the inflatable restraint IP module switch. Refer to Inflatable Restraint Instrument Panel Module Disable Switch Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
