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 | -- | -- | B0077 | -- | -- |
Side Impact Sensor Left Voltage | B0077 | B0077 | B0077 | B0077 | B0077 |
Side Impact Sensor Right Signal | -- | -- | B0078 | -- | -- |
Side Impact Sensor Right Voltage | 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 requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator. |
| • | 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
Description and Operation
SIR System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Important: Refer to SIR Service Precautions.
When removing connectors, inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector:| • | Front end sensor |
| • | SDM module |
| • | Front end sensor wiring harness connector |
| • | SDM wiring harness connector |
- Ignition OFF, disconnect the harness connector at the SDM and the appropriate side impact sensor.
- Ignition ON, test for less than 1-volt between the side impact sensor voltage circuit terminal B and ground.
- Ignition ON, test for less than 1-volt between the side impact sensor signal circuit terminal A and ground.
- Test for infinite resistance between the side impact sensor voltage circuit terminal B and ground.
- Test for less than 1 ohm between the side impact sensor voltage circuit terminals listed below:
- Test for less than 1 ohm between the side impact sensor signal circuit terminals listed below:
- If all circuits test normal, replace the appropriate side impact sensor.
- Reconnect all SIR components. Ignition ON, verify the DTC does not set as current.
| ⇒ | If greater than the specified range, test the voltage circuit for a short to voltage |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. |
| ⇒ | If less than the specified value, test the voltage circuit for a short to ground. |
| • | Right side impact sensor terminal B and SDM harness connector terminal C8. |
| • | Left side impact sensor terminal B and SDM harness connector terminal C5. |
| ⇒ | If greater than the specified range, test the voltage circuit for an open/voltage resistance. |
| • | Right side impact sensor terminal A and SDM harness connector terminal C7. |
| • | Left side impact sensor terminal A and SDM harness connector terminal C6. |
| ⇒ | If greater than the specified range, test the signal circuit for an open/high resistance. |
| ⇒ | If the DTC resets as current, replace the SDM. |
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. |
