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Home >> Chevrolet >> 2012 >> Volt >> Repair and Diagnosis >> Body & Frame >> Ignition Switch/Steering Lock >> Immobilizer System >> Diagnostic Information and Procedures >> DTC B2955 >> Circuit/System Testing

Circuit/System Testing

  1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the K89 immobilizer control module. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 30 Ω between the low reference circuit terminal 1 and ground.
    • If 30 Ω or greater 
    1. Vehicle OFF, disconnect the harness connector at the K9 BCM.
    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 K9 BCM.
    • If less than 30 Ω 
  3. Connect a test lamp between the B+ circuit terminal 3 and ground.
  4. Verify the test lamp illuminates or flashes for three seconds after ignition mode switch is pressed.
    • If the test lamp does not illuminate 
    1. Vehicle OFF, disconnect the harness connector at the K9 BCM.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 BCM.
    • If the test lamp illuminates 
  5. Vehicle in Service Mode.
  6. Test for 12-13 V between the serial data circuit terminal 2 and ground.
    • If less than 12 V 
    1. Vehicle OFF, disconnect the harness connector at the K9 BCM.
    2. Test for infinite resistance between the serial data circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the serial data circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 BCM.
    • If greater than 13 V 
    1. Vehicle OFF, disconnect the harness connector at the K9 BCM, vehicle ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K9 BCM.
    • If within 12-13 V 
  7. Replace the K89 immobilizer control module.
  8. Verify DTC B2955 is not set.
    • If DTC B2955 is set 

      Replace the K9 BCM.

    • If DTC B2955 is not set or is set as history 
  9. All OK.
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