DTC 077

Schematic:

CIRCUIT DESCRIPTION
When you first turn ON the ignition, the inflatable restraint sensing and diagnostic and seat belt pretensioner module (SDM) performs tests to diagnose critical malfunctions within itself. Then, the SDM proceeds with the RESISTANCE MEASUREMENT test to measure the deployment loop resistances to ensure that they are within their respective normal resistance ranges. During one portion of the RESISTANCE MEASUREMENT test, the SDM does the following:
^ Measures the voltage difference between the driver side high and driver side low circuits
^ Uses the measured voltage to calculate the resistance of the driver side air bag deployment loop

Upon passing these tests, the energy reserve is charged and the firing transistors are tested. The SDM then goes into the CONTINUOUS MONITORING mode

CONDITIONS FOR RUNNING THE DTC
When the ignition voltage is within the normal operating voltage range, the SDM performs the RESISTANCE MEASUREMENT test in order to calculate the resistance of the driver side air bag deployment loop.

CONDITIONS FOR SETTING THE DTC
The calculated resistance of the driver side air bag deployment loop is above 2.4 Ohm.

ACTION TAKEN WHEN THE DTC SETS
The SDM turns ON the AIR BAG warning lamp

CONDITIONS FOR CLEARING THE DTC
^ You can issue a CLEAR CODES command
^ A history DTC will clear once 255 malfunction free ignition cycles have occurred.

DIAGNOSTIC AIDS
The following can cause an intermittent condition:
^ The inflatable restraint side impact module 2-way connector.
^ The SDM wiring harness connector.
^ The wire to terminal connections in the driver side high circuit.
^ The wire to terminal connections in the driver side low circuit.
^ Refer to Testing for Intermittent and Poor Connections in Wiring Diagrams. Diagrams

TEST DESCRIPTION

Steps 1 - 6:

Steps 7 - 14:

The numbers below refer to step numbers on the diagnostic table.
2. This step checks the inflatable restraint side impact module 2-way connector.
7. This step checks the SDM wiring harness connector.
9. This step checks for an open or a high resistance in the driver side high circuit.
11. This step determines if there is an open or a high resistance in the driver side low circuit or if there is a malfunctioning SDM.