Circuit Description
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 chafing |
If any of the above conditions are found refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
Test the Left SIS signal and Left SIS ground circuits for an open or high resistance.
-
Test between the Left SIS signal and Left SIS ground circuits for resistance.
-
Test the Left SIS signal and Left SIS ground circuits for a short to voltage.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | ||||
1 | Did you perform A Diagnostic System Check - SIR? | -- | Go to Step 2 | |
2 |
Does connector exhibits any signs of damage or corrosion? | -- | Go to Step 3 | Go to Step 4 |
3 |
Did you complete the repair? | -- | Go to Step 12 | -- |
4 |
Does the scan tool indicate that DTC B0077 is current? | -- | Go to Step 5 | Go to Diagnostic Aids |
5 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7 | |
Test the resistance between the Left SIS signal circuit and the Left SIS ground circuit on the SDM connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Does the resistance measure less than the specified value? | OL | Go to Step 10 | Go to Step 8 | |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | |
9 | Replace the Left SIS. Refer to Inflatable Restraint Side Impact Sensor Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | Go to Step 11 | System OK |
11 |
Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
