Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B0077 : Driver Side Impact Sensor (SIS) PerformanceDTC B0078 : Passenger Side Impact Sensor (SIS) Performance
DTC B0079 : Incorrect Driver Side Impact Sensor (SIS) Installed
DTC B0080 : Discard Driver Side Impact Sensor (SIS)
DTC B0081 : Incorrect Passenger Side Impact Sensor (SIS) Installed
DTC B0082 : Discard Passenger Side Impact Sensor (SIS)
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
Side Impact Sensor Left Signal Circuit | -- | -- | B0077 | -- | -- |
Side Impact Sensor Left Voltage Circuit | B0077 | B0077 | B0077 | B0077 | B0077 |
Side Impact Sensor Right Signal Circuit | -- | -- | B0078 | -- | -- |
Side Impact Sensor Right Voltage Circuit | B0078 | B0078 | B0078 | B0078 | B0078 |
Circuit/System Description
The inflatable restraint side impact sensor (SIS) utilizes a unidirectional 2-wire circuit. The SIS modulates current on the interface to send ID, state of health (SOH), and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the SIS. When the ignition is turned ON and input power from the SDM is first detected, the SIS responds by performing internal diagnostics and sending an ID to the SDM. The SDM considers the ID to be valid if the response time is less than 5 seconds. The SIS continually communicates status messages to the SDM, which determines if a fault is present in the SIS circuit. When a fault is detected, the SDM resets the SIS twice by removing and reapplying power to it. If the fault is still present, the SDM will set a DTC.
Conditions for Running the DTC
Ignition voltage is between 9-16 volts.
Conditions for Setting the DTC
All of the following conditions exist for 2.5 seconds:
B0077 for SIS - LF or B0078 for SIS - RF
| • | A valid ID message is not received within 5 seconds of the SIS being powered up. |
| • | The SDM has not received a message from the SIS for more than 375 milliseconds. |
| • | The SDM has reset the SIS twice without detecting a valid ID message. |
B0079 for SIS - LF or B0081 for SIS - RF
| • | The SDM has received an ID message from the SIS which does not match the ID stored in the SDM memory. |
| • | The SDM has reset the SIS twice without detecting a correct ID message. |
B0080 for SIS - LF or B0082 for SIS - RF
The SDM has received a NOK message from the SIS.
Action Taken When the DTC Sets
| • | The SDM commands the AIR BAG indicator ON via serial data communications. |
| • | The SIR system is disabled and no deployments are allowed. |
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. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Circuit/System Testing
- Ignition ON, use the scan tool as clear SIR codes then recheck for DTCs. Verify that DTC B0079, B0080, B0081, or B0082 is not set.
- If DTC B0077 is current, disconnect the left SIS connector, or if DTC B0078 is current, disconnect the right SIS connector. Refer to SIS replacement in Repair Instructions for location of connector.
- Remove the SDM connector.
- Test the signal and voltage circuits between the SDM and SIS. Verify that a short to voltage, short to ground, or open/low resistance does not exist.
- Reconnect all SIR components. Ignition ON, use the scan tool to clear the DTCs then recheck for DTCs. Verify no DTCs are set.
Important: When removing connectors, inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.
• The SIS • The SDM module • The SIS wiring harness connector • The SDM wiring harness connector
| ⇒ | If DTC B0079 or B0080 is set current, replace the SIS left. |
| ⇒ | If DTC B0081 or B0082 is set current, replace the SIS right. |
| ⇒ | If any of the above conditions are found, make the appropriate repair. |
| ⇒ | If DTC B0077 was current, replace the left SIS. If DTC B0078 was current, replace the right SIS. After replacement, refer to Repair Verification. |
Repair Instructions
| • | Control Module References for SDM replacement, setup, and programming |
Repair Verification
Ignition ON, use the scan tool to clear the DTCs then recheck for DTCs. Verify no DTCs are set.
| ⇒ | If DTC B0077 or B0078 was current, replace the SDM. |
