Circuit Description
When you first turn the ignition switch to the ON position, the inflatable Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. Next the SDM measures IGNITION 1 and the deployment loop voltages to make sure they are within their respective normal voltage ranges. Then the SDM proceeds with the RESISTANCE MEASUREMENT test. During one portion of the RESISTANCE MEASUREMENT test, the SDM does the following:
| • | Grounds the DRIVER SIDE LOW terminal 10 through an internal current sink. |
| • | Connects the DRIVER SIDE HIGH terminal 9 to an internal constant current source. This current produces proportional voltage drops in the deployment loop. |
| Measure the voltage difference between the DRIVER SIDE HIGH and DRIVER SIDE LOW. |
| • | Calculates the resistance of the driver deployment loop using the measured voltage. |
Conditions for Setting the DTC
| • | The driver and passenger deployment loops are not open. |
| • | The driver and passenger deployment loops are not shorted to voltage. |
| • | The driver deployment loop is not shorted to ground. |
| • | The driver deployment loop resistance is less than 1.8 ohms. The driver deployment loop consists of the following components: |
| - | Inflatable restraint steering wheel module. |
| - | Inflatable restraint steering wheel module coil. |
| - | Harness wiring of the GRN/RED wire. |
| - | Harness wiring of the GRN wire. |
| - | Connector terminal contact. |
The RESISTANCE MEASUREMENT test checks for this malfunction. This test only occurs once each ignition cycle 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 ON the AIR BAG warning lamp. |
Conditions for Clearing the DTC
| • | Clear the Current DTC when the resistance of the driver deployment loop is more than 1.8 ohms and the ignition switch is cycled. |
| • | Clear the History DTC under the following conditions: |
| - | You issue a scan tool CLEAR CODES command. |
| - | 250 malfunction free ignition cycles have occurred. |
When you issue a scan tool CLEAR CODES command and the malfunction is still present, the DTC will not reappear until the next ignition cycle
Diagnostic Aids
the following can cause an intermittent condition:
| • | A short circuit between the GRN/RED wire and the GRN wire. |
| • | A short circuit between the GRN/RED wire and the YEL/RED wire. |
| • | A short circuit between the GRN/RED wire and the YEL wire. |
| • | A malfunctioning shorting bar on the inflatable restraint steering wheel module connector. |
| • | A malfunctioning shorting bar on the inflatable restraint steering wheel module coil steering column connector. |
The diagnostic table directs the technician to note the entry value of DRIVER RESISTANCE. Comparing the value of DRIVER RESISTANCE can 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 Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections . When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair in this section.
Test Description
Numbers below refer to step numbers on the diagnostic table.
-
This test determines the deployment loop resistance measured by the inflatable restraint Sensing and Diagnostic Module (SDM).
-
This test isolates the malfunction to one side of the yellow 2-way connector on the inflatable restraint steering wheel module coil. This connector is located near the base of the steering column.
-
This test determines whether the malfunction is in the inflatable restraint steering wheel module coil or the inflatable restraint steering wheel module.
-
This test checks for a short from the GRN/RED wire to the GRN wire.
-
This test checks for a short from the GRN/RED wire to the YEL wire.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | ||
Is DTC B1016 also current? | -- | |||
3 |
Is the circuit repair complete? | -- | -- | |
4 |
Is the DRIVER RESISTANCE less than the specified value? | 1.8ohms | ||
5 |
Have you replaced the yellow 2-way harness connector? | -- | -- | |
Is DRIVER RESISTANCE less than the specified value? | 1.8ohms | |||
Is DRIVER RESISTANCE less than the specified value? | 1.8ohms | |||
8 |
Have you replaced the inflatable restraint steering wheel module? | -- | -- | |
9 |
Have you replaced the inflatable restraint steering wheel module coil? | -- | -- | |
Is the resistance reading less than the specified value? | OL | |||
11 |
Is the repair complete? | -- | -- | |
Measure the resistance from the SDM harness connector terminal 9 to terminal 3. Is the resistance reading less than the specified value? | OL | |||
13 | Repair the short from the GRN/RED wire to the YEL wire. Is the repair complete? | -- | -- | |
14 | Reconnect and mount all the SIR system components. Have all the SIR components been reconnected and properly mounted? | -- | -- | |
15 | Clear the SIR diagnostic trouble codes. Have you cleared all the SIR diagnostic trouble codes? | -- | -- |
