Sensing and Diagnostic Module Integrity Check. Chevrolet Joy 2008

For 1990-2009 cars

The following diagnostic chart must be used when all circuitry outside the sensing and diagnostic module (SDM) has been found to operate properly, as indicated by following the appropriate diagnostic trouble code (DTC) chart. The chart verifies the need for SDM replacement.

### Circuit Description

When the SDM recognizes ignition voltage greater than 9 volts at terminal A10 of the SDM, the air bag indicator flashes 7 times to verify operation. At this time the SDM performs turn-on tests followed by resistance measurement tests and continuous monitoring tests.

When a malfunction is detected, the SDM sets a current DTC and illuminates the air bag indicator.

When the malfunction is no longer detected and/or the ignition switch is cycled, the SDM will clear current DTCs and move them to a history file, except for the DTC 051, 053, and sometimes 071. DTC 051 and 053 will not be cleared by the scan tool because these codes require replacement of the SDM. The SDM must be replaced only after the malfunction that set the DTC has been repaired.

Step | Action | Yes | No
--- | --- | --- | ---
Caution: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Caution in the Preface section. Caution: Refer to Sensing and Diagnostic Module Handling Caution in the Preface section. Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views

1

1. Turn the ignition to LOCK and remove the key.
2. Connect all SIR components and ensure that all the components are properly mounted.
3. Ensure that the ignition switch has been OFF for at least 30 seconds.
4. Observe the air bag indicator as the ignition is turned ON.

Does the indicator lamp flash 7 times and turn OFF?

Go to Diagnostic System Check - Vehicle

Go to Step 2

2

1. Turn the ignition to LOCK and remove the key.
2. Connect the scan tool to the data link connector (DLC).
3. Turn the ignition to ON.
4. Request the SIR DTC display with the scan tool.

Is the same DTC displayed?

Go to Step 3

Go to Diagnostic Trouble Code (DTC) List - Vehicle

3

1. Clear the SIR DTCs.
2. Turn the ignition OFF for at least 30 seconds.
3. Observe the air bag indicator as the ignition is turned ON.

Does the indicator lamp flash 7 times and turn OFF?

System OK

Go to Step 4

4

1. Turn the ignition to LOCK and remove the key.
2. Disconnect the sensing and diagnostic module (SDM) connector.
3. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
4. Connect the SDM connector and ensure that all components are properly mounted.

Is the repair complete?

Go to Diagnostic System Check - Vehicle

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