• | 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. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
Front End Sensor Left Signal | -- | -- | B0100 | -- | -- |
Front End Sensor Left Voltage | B0100 | B0100 | B0100 | B0100 | B0100 |
Front End Sensor Right Signal | -- | -- | B0103 | -- | -- |
Front End Sensor Right Voltage | B0103 | B0103 | B0103 | B0103 | B0103 |
The inflatable restraint front end sensor utilizes a unidirectional 2-wire circuit. The front end sensor modulates current on the interface to send ID, State of Health, and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the front end sensor. 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 front end sensor continually communicates status messages to the SDM, which determines if a fault is present in the front end sensor circuit. When a fault is detected, the SDM resets the front end sensor twice by removing and reapplying power to it. If the fault is still present, the SDM will set a DTC.
Ignition voltage is between 9-16 volts.
All of the following conditions exist for 2.5 seconds:
• | A valid ID message is not received within 5 seconds of the front end sensor being powered up. |
• | The SDM has not received a message from the front end sensor for more than 375 milliseconds. |
• | The SDM has reset the front end sensor twice without detecting a valid ID message. |
• | The SDM has received an ID message from the front end sensor, which does not match the ID stored in the SDM memory. |
• | The SDM has reset the front end sensor twice without detecting a correct ID message. |
The SDM has received a NOK message from the front end sensor.
• | The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator. |
• | The SIR System is disabled and no deployments are allowed. |
• | 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 100 malfunction-free ignition cycles have occurred. |
SIR System Description and Operation
Control Module References for scan tool information
Important: Refer to SIR Service Precautions.
When removing the connectors, inspect for damage or corrosion. Damage or corrosion to 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 |
⇒ | 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. |
⇒ | If less than the specified value, test the circuit for a short to ground. |
• | Right front end sensor terminal B and SDM harness connector terminal B8. |
• | Left front end sensor terminal B and SDM harness connector terminal B5. |
⇒ | If greater than the specified range, test the signal circuit for an open/high resistance. |
• | Right front end sensor terminal A and SDM harness connector terminal B7. |
• | Left front end sensor terminal A and SDM harness connector terminal B6. |
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. |
⇒ | If the DTC resets as current , replace the SDM. |
• | Control Module References for SDM replacement, setup, and programming |
Ignition ON, use the scan tool to clear the DTCs then recheck for DTCs. Verify no DTCs are set.
⇒ | If DTC B0100 or B0103 was current replace the SDM. |