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. Then the SDM 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 Setting the DTC
| • | Deployment loop voltage out of range test. |
| - | Ignition 1 voltage is within the normal operating voltage range. |
| - | Passenger frontal high terminal A3 is more than 6 volts for 300 milliseconds. |
| • | Deployment loop resistance measurement test. |
| - | Ignition 1 voltage is within the normal operating voltage range. |
| - | Passenger frontal deployment loop is not shorted to voltage. |
| - | Passenger frontal high terminal A3 is less than 2 volts AND passenger frontal deployment loop resistance is less than 6 ohms for 300 milliseconds. |
The passenger frontal deployment loop consists of the following components:
| • | Inflatable restraint IP module. |
| • | Harness wiring of CKT 1403. |
| • | Harness wiring of CKT 1404. |
| • | Connector terminal contact. |
Action Taken When the DTC Sets
| • | The SDM sets a DTC B0018. |
| • | The SDM commands ON the AIR BAG warning lamp via Class 2 serial data. |
Conditions for Clearing the DTC
| • | Current DTC |
| - | Deployment loop voltage out of range test-Passenger frontal high terminal A3 is no more than 6 volts. |
| - | Deployment loop resistance measurement test-Passenger frontal high terminal A3 is more than 2 volts AND Passenger frontal deployment loop resistance is less than 6 ohms for 300 milliseconds. |
| • | History DTC |
| - | You issue a scan tool CLEAR CODES command. |
| - | Once 250 malfunction free ignition cycles have occurred. |
Diagnostic Aids
A short to B+ or ground in the inflatable restraint IP module circuit can cause an intermittent condition. Inspect CKT 1403 and CKT 1404 carefully for cutting or chafing. Wiring pigtail damage requires replacement of the inflatable restraint IP module.
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
This step checks the inline connector C219.
-
This step checks to see if there is a malfunctioning inflatable restraint IP module.
-
This step checks to see if there is a short to ground in CKT 1403.
-
This step checks to see if there is a short to ground in CKT 1404.
-
This step checks to see if there is a short to B+ in CKT 1403.
-
This step determines if there is a short to B+ in CKT 1404 or if there is a malfunctioning SDM.
-
This step clears all SIR DTCs and also DTC U1088.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | ||
Is the wiring harness connector OK? | -- | |||
3 | Replace the wiring harness side of inline connector C219. Refer to Wiring Repair . Is the repair complete? | -- | -- | |
4 |
Is DTC B0018 current? | -- | ||
Is DTC B0018 current? | -- | |||
6 |
Is the repair complete? | -- | -- | |
Is the measured resistance less than the specified value? | OL | |||
8 |
Is the repair complete? | -- | -- | |
Use the DMM to measure the resistance between terminal A8 of the SDM wiring harness connector and a known good ground. Is the measured resistance less than the specified value? | OL | |||
10 |
Is the repair complete? | -- | -- | |
Is the measured voltage less than the specified value? | 1V | |||
12 |
Is the repair complete? | -- | -- | |
Use the DMM to measure the voltage between terminal A8 of the SDM wiring harness connector and a known good ground. Is the measured voltage less than the specified value? | 1V | |||
14 |
Is the repair complete? | -- | -- | |
15 |
Is the repair complete? | -- | -- | |
Have all current and history DTCs been cleared? | -- | -- |
