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| • | 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 |
|---|---|---|---|---|---|
Centre Front Impact Sensor High Signal | B0091 02 | B0091 04 | B0091 0C , B0091 04 | B0091 01, B0091 05 | B0091 39, B0091 71 |
Centre Front Impact Sensor Low Reference | B0091 02 | B0091 04 | B0091 0C , B0091 04 | B0091 01 | B0091 39, B0091 71 |
The impact sensors are equipped on vehicles to supplement the Supplemental Inflatable Restraint (SIR) System performance. The impact sensors are electronic and are not part of the deployment loops, but instead provide inputs to the inflatable restraint sensing and diagnostic module (SDM). The impact sensors can assist in determining the severity of some frontal and side collisions. The SDM uses the input from the impact sensors to assist in determining the severity of a collision further supporting air bag deployment. If the SDM determines a deployment is warranted, the SDM will cause current to flow through the deployment loops deploying the appropriate air bags. The centre front impact sensor and side impact sensors utilise a bidirectional 2-wire circuit. The sensors modulate current on the interface to send identification, state of health, and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and an ground for the sensors. When the ignition is turned ON and input power from the SDM is first detected, the sensors respond by performing internal diagnostics and sending an identification to the SDM. The SDM considers the identification to be valid if the response time is less than 5 seconds. The sensors continually communicate 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 sensors 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 V.
The SDM has detected the centre front impact sensor has been shorted to voltage
| • | The SDM has detected the centre front impact sensor has been shorted to ground. |
| • | The centre front impact sensor current is greater than 23 mA for greater than 5 milliseconds. |
| • | The SDM has detected an open/high resistance in the centre front impact sensor. |
| • | The SDM has not received a message from the centre front impact sensor for greater than 375 milliseconds. |
| • | The SDM has detected the centre front impact sensor has been shorted to voltage. |
| • | The SDM has detected an open/high resistance in the centre front impact sensor. |
| • | The SDM has not received a message from the centre front impact sensor for greater than 375 milliseconds. |
| • | The SDM has received a Not OK (NOK) message from the centre front impact sensor. |
| • | The SDM has not received a message. |
| • | The SDM has received identification message from the centre front impact sensor which does not match the identification stored in the SDM memory. |
| • | The SDM has reset the centre front impact sensor twice without detecting the correct identification message. |
The SDM has received invalid serial data from the centre front impact sensor.
| • | The SDM requests the instrument panel cluster to illuminate the AIR BAG indicator. |
| • | 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
If 10 Ω or greater
| 3.1. | Ignition OFF, disconnect the X2 harness connector at the K36 SDM. |
| 3.2. | Test for less than 2 Ω in the low reference circuit end to end. |
If 2 Ω or greater, repair the open/high resistance in the circuit.
If less than 2 Ω, replace the K36 SDM.
If less than 10 Ω
If 50k Ω or less
| 4.1. | Disconnect the X2 harness connector at the K36 SDM. |
| 4.2. | Test for infinite resistance between the signal circuit and ground. |
If less than infinite resistance, repair the short to ground on the circuit.
If infinite resistance, replace the K36 SDM.
If greater than 50k Ω
If 2 Ω or greater
If less than 2 Ω
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for SDM replacement, programming and setup |
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