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 - Left Front or B0078 for SIS - Right Front
| • | 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 - Left Front or B0081 for SIS - Right Front
| • | 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 - Left Front or B0082 for SIS - Right Front
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
- Verify DTC B0079, B0080, B0081, or B0082 is not set.
- Disconnect the harness connector at the applicable impact sensor and the SDM.
- Test for infinite resistance between the applicable impact sensor signal circuit terminal A and ground.
- Ignition ON, test for less than 1 volt between the applicable impact sensor signal circuit terminal A and ground.
- Ignition ON, test for less than 1 volt between the applicable impact sensor voltage circuit terminal B and ground.
- Test for less then 1 ohm between the applicable impact sensor and SDM signal circuit terminals listed below:
- Test for less then 1 ohm between the applicable impact sensor and SDM voltage circuit terminals listed below:
- If the circuits test normal, replace the applicable impact sensor.
- Reconnect all SIR components
- Verify DTC B0077 or B0078 is not 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.
• SIS • SDM module • SIS wiring harness connector • SDM wiring harness connector
| ⇒ | If DTC is set , replace the applicable impact sensor. |
| ⇒ | If less than the specified value, test the circuit for a short to ground. |
| ⇒ | If greater than the specified range, test the circuit for a short to voltage. |
| ⇒ | If greater than the specified range, test the circuit for a short to voltage. |
| • | Left front end sensor terminal B and SDM terminal 5 |
| • | Right front end sensor terminal B and SDM terminal 6 |
| ⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
| • | Left front end sensor terminal A and SDM terminal 26 |
| • | Right front end sensor terminal A and SDM terminal 27 |
| ⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
| ⇒ | If DTC is set, replace the SDM. |
Repair Instructions
| • | Control Module References for SDM replacement, setup, and programming |
