• | 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 |
---|---|---|---|---|---|
SIR Forward Sensor Signal Circuit | B0083 02 | B0083 05 | B0083 05 | B0083 05 | -- |
Left Front Discriminating Low Reference Circuit | -- | B0083 05 | B0083 05 | B0083 05 | -- |
Right Front Discriminating Sensor Signal Circuit | B0084 02 | B0084 05 | B0084 05 | B0084 05 | -- |
Right Front Discriminating Low Reference Circuit | -- | B0084 05 | B0084 05 | B0084 05 | -- |
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 front end sensor 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 may reset the front end sensor up to 2 times 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:
• | The front end sensor has been shorted to ground. |
• | The front end sensor current has been above 23 mA for longer than 5 milliseconds. |
• | The front end sensor has been shorted to voltage. |
• | The front end sensor circuit is open. |
• | The SDM has not received a message from the front end sensor for more than 375 milliseconds. |
The SDM has received erratic messages from the front end sensor.
• | The SDM has received a NOK message from the front end sensor. |
• | The SDM has not received a 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 the correct ID message. |
The SDM has received invalid serial data from the front end sensor.
• | The SDM commands the AIR BAG indicator ON via serial data communications. |
• | 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 255 malfunction-free ignition cycles have occurred. |
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 front end sensor • The SDM module • The front end sensor wiring harness connector • The SDM wiring harness connector
⇒ | If less than infinite resistance, 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. |
⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
⇒ | If the front end sensor DTC returns and is current, replace the SDM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for SDM replacement, setup, and programming |