Circuit Description
The inflatable restraint front end discriminating sensor is a crash sensing device used in the detection of a frontal collision. The front end discriminating sensor is used by the inflatable restraint sensing and diagnostic module (SDM) to help determine whether or not certain frontal crashes are severe enough to warrant deployment of the frontal air bags. The SDM applies voltage to the discriminating sensor - reference circuit and monitors the voltage at the discriminating sensor - signal circuit in order to verify proper circuit integrity. If the SDM detects a malfunction within the discriminating sensor circuit, a DTC will be set.
Conditions for Running the DTC
Ignition 1 Voltage is within the normal operating voltage range.
Conditions for Setting the DTC
The SDM detects a malfunction in the inflatable restraint front end discriminating sensor - left circuit.
Action Taken When the DTC Sets
The SDM commands the AIR BAG indicator ON.
Conditions for Clearing the DTC
The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
Diagnostic Aids
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.
The following are possible causes of the malfunction:
| • | An open or high resistance in the front end discriminating sensor - left circuits |
| • | A short to ground or voltage in the front end discriminating sensor - left circuits |
| • | An internal front end discriminating sensor - left malfunction |
| • | An internal SDM malfunction |
If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Tests the front end discriminating sensor for the proper resistance value.
-
Tests for an open, short to ground, or short to voltage in the front end discriminating sensor - left circuits.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | ||||||||||
1 | Did you perform A Diagnostic System Check - SIR? | -- | Go to Step 2 | |||||||
2 |
Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 3 | ||||||
Measure the resistance between the front end discriminating sensor - left terminals. Refer to Circuit Testing in Wiring Systems. Does the resistance measure as specified? | Approximately 820 ohms | Go to Step 4 | Go to Step 6 | |||||||
4 |
Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 5 | ||||||
Test the front end discriminating sensor - left - signal and the front end discriminating sensor - left - reference circuits for the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 7 | |||||||
6 | Replace the Inflatable Restraint Front End Discriminating Sensor - Left. Refer to Inflatable Restraint Front End Discriminating Sensor Replacement - Left Side . Did you complete the replacement? | -- | Go to Step 8 | -- | ||||||
7 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | Go to Step 8 | -- | ||||||
8 |
Does the DTC reset? | -- | Go to Step 2 | System OK | ||||||
