DTC 37

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

When the ignition switch is turned to "ON," the SDM will perform tests to diagnose critical malfunctions within itself. Upon passing these tests "Ignition 1," 23 VLR and deployment loop voltages are measured to ensure they are within their respective normal voltage ranges. The SDM then proceeds to Continuous Monitoring." The SDM contains a resistor network connected to "Ignition 1," ground, and to "Low Pressure Sensor" terminal "11." When the passenger inflator module is connected, the 1.0K ohms resistor and the normally closed switch provide a parallel path to ground causing a specific percentage of "Ignition 1" voltage to appear at "Low Pressure Sensor." This voltage is monitored to detect shorts to ground.

DTC WILL SET WHEN

"Ignition 1" is within the normal operating voltage range and the SDM is configured for a low pressure switch. Once these conditions are met and the voltage measured at the low pressure switch input is below a specified value for 500 milliseconds, DTC 37 will set.

ACTION TAKEN

SDM turns "ON" the "AIR BAG" warning lamp and sets DTC 37.

DTC CLEAR SET WHEN

The voltage measured at "Low Pressure Sensor" terminal "11" is greater than a specified percentage of "Ignition 1" voltage for 500 milliseconds during "Continuous Monitoring."

DTC CHART TEST DESCRIPTION

Numbers below refer to circled numbers on the diagnostic chart.

1. This test checks for a short across the low pressure switch circuit inside the passenger inflator module.

2. This test checks for a short from the low pressure switch circuit to ground.

DIAGNOSTIC AIDS

Intermittent shorts or opens can be located by, moving wires while monitoring the "AIR BAG warning lamp. An intermittent condition is likely to be caused by a short from CKT B1 to ground or a malfunction in the low pressure switch circuit inside the passenger inflator module which would require replacement of the passenger inflator module.