B0077

CIRCUIT DESCRIPTION

SIR Schematics: Standard Air Bags (Power, Grounds And Side Impact Sensors):

SIR Schematics: Standard Air Bags (Inflator Modules):

SIR Schematics: Dual Stage Air Bags (Power, Ground And Sensors):

SIR Schematics: Dual Stage Air Bags (Module Controls):

The inflatable restraint side impact sensor (SIS) - Left loop is a 2 wire circuit. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM provides input power to the SIS. When input power is first detected, the SIS responds by performing internal diagnostics. Next the SIS sends an ID message to the SDM. The SDM will consider this to be a valid ID if the response time is less than 5 seconds after the SIS is powered up. The SIS will continually communicate a status message to the SDM. The SDM can reset the SIS by removing and applying power to it.

CONDITIONS FOR RUNNING THE DTC
^ Ignition 1 Voltage is within the normal operating voltage range.
^ Left SIS loop is not shorted to voltage.
^ Left SIS loop is not shorted to ground. The SDM monitors the inflatable restraint side impact sensor (SIS) loop with the power on.

CONDITIONS FOR SETTING THE DTC
^ The SDM has detected one of the following conditions due to a fault in the SIS interface circuit:
- A valid ID message is not received within 5 seconds of the SIS being powered up.
- Status message is not received.
^ The SDM has failed twice to reset the SIS.

ACTION TAKEN WHEN THE DTC SETS
The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

CONDITIONS FOR CLEARING THE DTC
^ The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
^ A history DTC will clear once 255 malfunction free ignition cycles have occurred.

DIAGNOSTIC AIDS
The following can cause an intermittent condition in the SIS circuit:
^ A short to ground or short to voltage in the SIS circuit.
^ High or low resistance in the SIS circuit.
^ Inspect the SIS signal and ground circuits carefully for cutting and/or chating

If any of the above conditions are found refer to Testing for Intermittent and Poor Connections in Diagrams. Diagnostic Aids

TEST DESCRIPTION

Steps 1-3:

Steps 4-12:

The number(s) below refer to the step number(s) on the diagnostic table.
6. Test the Left SIS signal and Left SIS ground circuits for an open or high resistance.
7. Test between the Left SIS signal and Left SIS ground circuits for resistance.
8. Test the Left SIS signal and Left SIS ground circuits for a short to voltage.