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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 297 (Supplemental Restraints System) >> Diagnostic Information and Procedures >> DTC B1491 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT5. However, it is still accessible from the selected car via links, so may be relevant.
    NOTE:
    • Refer to SIR Service Precautions .
    • Refer to SIR Disabling and Enabling .
    • inspect the terminals of the following components and connectors for damage or corrosion and repair or replace as necessary:
      • B61P Seat Belt Tension Sensor - Passenger
      • K85P Restraint Occupant Classification System Module - Passenger
      • Inline Harness Connector
    • The connector and connector position assurance (CPA) may seat independent of each other. Both the connector and CPA should seat with an audible and/or tactile click.
  1. Ignition/Vehicle & All vehicle systems OFF
  2. Disconnect the harness connector at the B61P Seat Belt Tension Sensor - Passenger
  3. Test for less than 10 Ω between low reference circuit terminal 1 and ground
    • If 10 Ω or greater 
    1. Test circuit 3946 for an open.
      • If an open circuit is found, repair the fault on the circuit.
      • Go to next step: If an open circuit is not found
    2. Replace the K85P Restraints Occupant Classification System Control Module
    • Go to next step: If less than 10 Ω 
  4. Ignition On / Vehicle In Service Mode
  5. Test for less than 6 V between the test points: Signal circuit terminal 2 and Ground.
    • If 6 V or greater 
    1. Ignition/Vehicle & All vehicle systems OFF
    2. Disconnect the electrical connector K85P Restraint Occupant Classification System Module - Passenger
    3. Ignition ON / Vehicle In Service Mode
    4. Test Circuit 3947 for short to voltage
      • If short to voltage is found, repair the fault on the circuit.
      • Go to next step: If short to voltage is not found
    5. Replace K85P Restraint Occupant Classification System Module - Passenger
    • Go to next step: If less than 6 V 
  6. Ignition/Vehicle & All vehicle systems OFF
  7. Test for greater than 5 kΩ between the test points: Signal circuit terminal 2 and Ground
    • If 5 kΩ or less 
    1. Disconnect the K85P Restraint Occupant Classification System Module - Passenger
    2. Test circuit 3947 for short to ground
      • If short to ground found, repair the fault on the circuit
      • Go to next step: If infinite resistance
    3. Replace the K85P Restraint Occupant Classification System Module - Passenger
    • Go to next step: If Greater than 5 kΩ 
  8. Disconnect the K85P Restraint Occupant Classification System Module - Passenger
  9. Test for less than 2 Ω between the test points: Signal circuit terminal 2 at B61P Seat Belt Tension Sensor - Passenger and The other end of the circuit at Control module harness
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 Ω 
  10. If all conditions test normal = Replace the B61P Seat Belt Tension Sensor - Passenger
  11. Operate the vehicle within the Conditions for Running the DTC
  12. Verify the DTC B1491 is not set.
    • If the DTC is set 

      Replace the K85P Restraint Occupant Classification System Module - Passenger

    • Go to next step: If the DTC is not set 
  13. A fault is not currently present and may be an intermittent condition.
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