When you first turn the ignition switch to the ON position, The inflatable restraint 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 Passenger Side Low terminal 3 through an internal current sink. |
• | Connects the Passenger Side High terminal 4 to an internal constant current source . This current produces proportional voltage drops in the deployment loop. |
• | Measures the voltage difference between the Passenger Side High and Passenger Side Low. |
• | Calculates the resistance of the passenger deployment loop using the measured voltage. |
• | The driver and passenger deployment loops are not open. |
• | The driver and passenger deployment loops are not shorted to voltage. |
• | The passenger deployment loop is not shorted to ground. |
• | The passenger deployment loop resistance is less than 1.4 ohms. The passenger deployment loop consists of the following components: |
- | An inflatable restraint IP module. |
- | A harness wiring of the YEL /RED wire. |
- | A harness wiring of the YEL wire. |
- | A connector terminal contact. |
The Resistance Measurement test checks for this malfunction. This test only occurs once each ignition cycle when the IGNITION 1 is within the normal operating voltage range.
• | The SDM sets a diagnostic trouble code. |
• | The SDM turns ON the AIR BAG warning lamp. |
• | Clear the Current DTC when the resistance of the passenger deployment loop is more than 1.4 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.
The following can cause an intermittent condition:
• | A short circuit between the YEL/RED wire and the GRN /RED wire. |
• | A short circuit between the YEL/RED wire and the GRN wire. |
• | A short circuit between the YEL/RED wire and the YEL wire. |
• | A malfunctioning shorting bar on the inflatable restraint IP module connector. |
When a scan tool CLEAR CODES command is still present, the DTC will not reappear until the next ignition cycle. |
The numbers below refer to the step numbers on the diagnostic table.
This test determines the deployment loop resistance that the Sensing and Diagnostic Module (SDM) measures.
This test isolates the malfunction to one side of the yellow connector of the inflatable restraint IP module. This is done by substituting the known good resistance of the load tool, then observing if the malfunction is still present.
This test checks for a short from the YEL/RED wire to the YEL wire.
This test checks for a short from the YEL/RED wire to the GRN wire.
Step | Action | Values | Yes | No |
---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | ||
Is DTC B1022 also current? | -- | |||
3 |
Is the circuit repair complete? | -- | -- | |
4 |
Is PASSENGER RESISTANCE less than the specified value? | 1.4 ohms | ||
5 |
Did you replace the harness connector of the inflatable restraint IP module? | -- | -- | |
Is PASSENGER RESISTANCE less than the specified value? | 1.4 ohms | |||
7 |
Did you replace the inflatable restraint IP module? | -- | -- | |
Is the resistance reading less than the specified value? | OL (Infinite) | |||
9 |
Is the short repair complete? | -- | -- | |
Measure the resistance from the SDM harness connector terminal 4 to terminal 10. Is the resistance reading less than the specified value? | OL (Infinite) | |||
11 | Repair the short from the YEL/RED wire to the GRN wire. Is the short repair complete? | -- | -- | |
12 |
Are all the SIR components connected and correctly mounted? | -- | -- | |
13 | Clear the SIR diagnostic trouble codes. Did you clear the SIR diagnostic trouble codes? | -- | -- |