• | 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 |
---|---|---|---|---|---|
LF Side Impact Sensor High Signal | B0085 02 | B0085 71 | B0085 01 | B0085 01 | B0085 0F |
LF Side Impact Sensor Low Reference | -- | B0085 71 | B0085 01 | -- | B0085 0F |
RF Side Impact Sensor High Signal | B0086 02 | B0086 71 | B0086 01 | B0086 01 | B0086 0F |
RF Side Impact Sensor Low Reference | -- | B0086 71 | B0086 01 | -- | B0086 0F |
The inflatable restraint side impact sensor utilizes a 2-wire circuit. The side impact sensor receives 25 volts from the inflatable restraint sensing and diagnostic module (SDM). The side impact sensor modulates the voltage in order to send ID, state of health, and deployment commands to the SDM. When the ignition is turned ON and input power from the SDM is first detected, the side impact 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 side impact sensor continually communicates status messages to the SDM, which determines if a fault is present in the sensor circuit. When a fault is detected, the SDM may reset the side impact sensor up to 2 times by removing and reapplying power to it. If the fault is still present, DTC B0085 or B0086 and the appropriate symptom byte sets.
Ignition voltage is between 9-16 volts.
All of the following conditions exist for 2.5 seconds:
• | The side impact sensor signal circuit voltage is greater than the expected value. |
• | The SDM did not receive a message from the side impact sensor for more than 375 milliseconds |
• | The side impact sensor signal circuit is shorted to ground. |
• | The side impact sensor current is greater than 23 mA for greater than 5 milliseconds. |
The SDM received erratic messages from the side impact sensor.
The SDM received a NOK message from the side impact sensor.
• | The SDM received an ID message from the side impact sensor that does not match the ID stored in the SDM memory. |
• | The SDM has reset the side impact sensor twice without detecting the correct ID message. |
The SDM received invalid serial data from the side impact sensor.
• | The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator and display the message "Service Air Bag". |
• | The SIR System is disabled and no deployments are allowed. |
• | The condition for setting the DTC no longer exists. |
• | 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 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 |
• | Side impact sensor low reference circuit terminal A and ground. |
• | Side impact sensor signal circuit terminal B and ground. |
⇒ | If less than the specified value, test the voltage circuit for a short to ground. |
• | Right side impact sensor terminal A and SDM harness connector terminal 48 |
• | Right side impact sensor terminal B and SDM harness connector terminal 49. |
• | Left side impact sensor terminal A and SDM harness connector terminal 47. |
• | Left side impact sensor terminal B and SDM harness connector terminal 46. |
⇒ | If greater than the specified range, test the circuit for an open/voltage resistance. |
⇒ | If the DTC resets as current, replace the SDM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for SDM replacement, setup, and programming |