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DTC B0091

Diagnostic Instructions
    • 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.

DTC Descriptors

DTC B0091 01: Centre Front Impact Sensor Short to Battery

DTC B0091 02: Centre Front Impact Sensor Short to Ground

DTC B0091 04: Centre Front Impact Sensor Open Circuit

DTC B0091 05: Centre Front Impact Sensor High Voltage/Open

DTC B0091 0C: Centre Front Impact Sensor Low Current

DTC B0091 39: Center Front Impact Sensor Internal Malfunction

DTC B0091 3A: Centre Front Impact Sensor Incorrect Component Installed

DTC B0091 71: Center Front Impact Sensor Invalid Data

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Signal

B0091 02

B0091 04

B0091 0C , B0091 04

B0091 01, B0091 05

B0091 39, B0091 71

Low Reference

B0091 02

B0091 04

B0091 0C , B0091 04

B0091 01

B0091 39, B0091 71

Circuit/System Description

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 a 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.

Conditions for Running the DTC

Ignition voltage is between 9-16 V.

Conditions for Setting the DTC

B0091 01

The SDM has detected the centre front impact sensor has been shorted to voltage

B0091 02

    • 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.

B0091 04

    • 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.

B0091 05 and B0091 0C

    • 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.

B0091 39

    • The SDM has received a Not OK (NOK) message from the centre front impact sensor.
    • The SDM has not received a message.

B0091 3A

    • 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.

B0091 71

The SDM has received invalid serial data from the centre front impact sensor.

Action Taken When the DTC Sets
    • The SDM requests the instrument panel cluster to illuminate the AIR BAG indicator.
    • The SIR system is disabled and no deployments are allowed.

Conditions for Clearing the DTC
    • The condition for setting the DTC no longer exists.
    • A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

SIR System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Connector Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Note: Refer to SIR Service Precautions .

Inspect all terminals for damage or corrosion when disconnecting connectors. Damage or corrosion in the following requires repair or replacement of the affected component/connector.

   • Front impact sensor
   • Side impact sensor
   • SDM
   • Front impact sensor wiring harness connector
   • Side impact sensor wiring harness connector
   • SDM wiring harness connector

Note: The connector and connector position assurance (CPA) may seat independently of each other. Both the connector and CPA should seat with an audible and/or tactile click. The CPA isolates the shorting-bars within the connector allowing the deployment circuit to operate properly. Replace any CPA that is damaged or missing.

If the condition is intermittent or cannot be duplicated, disconnect the connectors and add Nyogel lubricant 760G. This procedure will correct the high resistance condition due to terminal fretting corrosion.

  1. Verify that DTC B0091 symptom byte 39 or 71 is not set as current.
    2. [ARW-LISTFAIL]

  2. If DTC B0091 symptom byte 39 or 71 is set as current

    Replace the B59 front impact sensor.

    3. [/ARW-LISTFAIL][ARW-LISTPASS]

  3. If DTC B0091 symptom byte 39 or 71 is not set as current

    4. [/ARW-LISTPASS]
  4. Verify that DTC B0091 symptom byte 3 A is not set as current.
    5. [ARW-LISTFAIL]

  5. If DTC B0091 symptom byte 3 A is set as current

    Replace the incorrect B59 front impact sensor

    6. [/ARW-LISTFAIL][ARW-LISTPASS]

  6. If DTC B0091 symptom byte 3 A is not set as current

    7. [/ARW-LISTPASS]
  7. Verify that DTC B0091 symptom byte 01, 02, 04, or 05 is not set as current.
    8. [ARW-LISTFAIL]

  8. If DTC B0091 symptom byte 01, 02, 04, or 05 is set as current

    Refer to Circuit/System Testing.

    9. [/ARW-LISTFAIL][ARW-LISTPASS]

  9. If DTC B0091 symptom byte 01, 02, 04, 05 is not set as current

    10. [/ARW-LISTPASS]
  10. All OK.

Circuit/System Testing
  1. Ignition OFF. Disconnect the harness connector at the B59 front impact sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal 2 and ground.
    3. [ARW-LISTFAIL]

  3. If 10 Ω or greater

    4. [/ARW-LISTFAIL]
    2.1. Ignition OFF, disconnect the X2 harness connector at the K36 SDM.
    2.2. Test for less than 2 Ω in the low reference circuit end to end.
    [ARW-LISTFAIL]

  4. If 2 Ω or greater, repair the open/high resistance in the circuit.

  5. If less than 2 Ω, replace the K36 SDM.

    6. [/ARW-LISTFAIL] [ARW-LISTPASS]

  6. If less than 10 Ω

    7. [/ARW-LISTPASS]
  7. Ignition ON.
  8. Test for less than 11 V between the signal circuit terminal 1 and ground.
    9. [ARW-LISTFAIL]

  9. If 11 V or greater

    10. [/ARW-LISTFAIL]
    4.1. Ignition OFF. Disconnect the X2 harness connector at the K36 SDM. Ignition ON.
    4.2. Test for less than 1 V between the signal circuit terminal 1 and ground.
    [ARW-LISTFAIL]

  10. If 1 V or greater, repair the short to voltage on the circuit.

  11. If less than 1 V, replace the K36 SDM.

    12. [/ARW-LISTFAIL] [ARW-LISTPASS]

  12. If 11 V or less

    13. [/ARW-LISTPASS]
  13. Ignition OFF.
  14. Test for greater than 50k Ω between the signal circuit terminal 1 and ground.
    15. [ARW-LISTFAIL]

  15. If 50k Ω or less

    16. [/ARW-LISTFAIL]
    6.1. Disconnect the X2 harness connector at the K36 SDM.
    6.2. Test for infinite resistance between the signal circuit and ground.
    [ARW-LISTFAIL]

  16. If less than infinite resistance, repair the short to ground on the circuit.

  17. If infinite resistance, replace the K36 SDM.

    18. [/ARW-LISTFAIL] [ARW-LISTPASS]

  18. If greater than 50k Ω

    19. [/ARW-LISTPASS]
  19. Disconnect the X2 harness connector at the K36 SDM.
  20. Test for less than 2 Ω between the signal circuit end to end from the B59 front impact sensor terminal 1 and the K36 SDM terminal 23 X2.
    21. [ARW-LISTFAIL]

  21. If 2 Ω or greater

    Repair the open/high resistance in the circuit.

    22. [/ARW-LISTFAIL][ARW-LISTPASS]

  22. If less than 2 Ω

    23. [/ARW-LISTPASS]
  23. Verify that the K36 SDM calibrations match the VIN data, software part number, and calibration part number.
    24. [ARW-LISTFAIL]

  24. If the K36 SDM calibrations do not match the VIN data

    Program the K36 SDM, refer to Inflatable Restraint Sensing and Diagnostic Module Programming and Setup .

    25. [/ARW-LISTFAIL][ARW-LISTPASS]

  25. If the K36 SDM calibrations match the VIN data

    26. [/ARW-LISTPASS]
  26. Replace the B59 front impact sensor.
  27. Verify the DTC does not set while operating the vehicle under the conditions for setting the DTC.
    28. [ARW-LISTFAIL]

  28. If the DTC sets

    Replace the K36 SDM.

    29. [/ARW-LISTFAIL][ARW-LISTPASS]

  29. If the DTC does not set

    30. [/ARW-LISTPASS]
  30. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

    •  Front End Inflatable Restraint Discriminating Sensor Replacement
    • Control Module References for SDM replacement, programming and setup
   


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