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Home >> Chevrolet >> 2021 >> Bolt EV Premier >> Repair and Diagnosis >> Body & Frame >> Ignition Switch/Steering Lock >> Immobilizer System >> Diagnostic Information and Procedures >> DTC B2955 >> Circuit/System Testing
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Circuit/System Testing

    NOTE:

    Some control module ground circuits may require up to 2 min after the ignition is turned Off before achieving a resistance reading of less than 5 Ω. In most cases the readings will drop below 20 Ω within 1 min indicating the control modules are going to sleep.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: K89 Immobilizer Control Module
  3. Verify a test lamp turns On between the test points: Low Reference circuit terminal 1 & B+
    • If the test lamp does not turn On 
    1. Disconnect the electrical connector: K9 Body Control Module
    2. Test for less than 2 Ω between the test points: Low Reference circuit terminal 1 @ Component harness & Low Reference circuit terminal 1 @ Control module harness
      • If 2 Ω or greater - Repair the open/high resistance in the circuit.
      • If less than 2 Ω - Replace the component: K9 Body Control Module
    • Go to next step: If the test lamp turns On 
  4. Ignition - On/Vehicle - In Service Mode
    5. NOTE:

    The voltage will only be present for 3 s after the ignition/vehicle is turned On.

  5. Test for greater than 9 V between the test points: Ignition circuit terminal 3 & Ground
    • If 9 V or less 
    1. Disconnect the electrical connector: K9 Body Control Module
    2. Test for infinite resistance between the test points: Ignition circuit terminal 3 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    1. Test for less than 2 Ω between the test points: Ignition circuit terminal 3 @ Component harness & Ignition circuit terminal 3 @ Control module harness
      • If 2 Ω or greater - Repair the open/high resistance in the circuit.
      • If less than 2 Ω - Replace the component: K9 Body Control Module
    • Go to next step: If greater than 9 V 
  6. Test for 10 to 13 V between the test points: Signal circuit terminal 2 & Ground
    • If less than 10 V 
    1. Ignition/Vehicle & All vehicle systems - Off
    2. Test for infinite resistance between the test points: Signal circuit terminal 2 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω between the test points: Signal circuit terminal 2 @ Component harness & Signal circuit terminal 2 @ Control module harness
    • If 2 Ω or greater - Repair the open/high resistance in the circuit.
    • If less than 2 Ω - Replace the component: K9 Body Control Module
    • If greater than 13 V 
    1. Disconnect the electrical connector: K9 Body Control Module
    2. Test for less than 1 V between the test points: Signal circuit terminal 2 & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K9 Body Control Module
    • Go to next step: If between 10 and 13 V 
  7. Replace the component: K89 Immobilizer Control Module
  8. Operate the vehicle within the Conditions for Running the DTC.
  9. Verify DTC B2955 is not set.
    • If the DTC sets 

      Replace the component: K9 Body Control Module

    • Go to next step: If the DTC is not set 
  10. All OK.
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