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Home >> Chevrolet >> 2017 >> SS Automatic Trans >> Repair and Diagnosis (Single Page) >> Body & Frame >> Ignition Switch/Steering Lock >> Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC B144B: Run/Crank Power Relay Circuit >> Circuit/System Testing

Circuit/System Testing

  1. Ignition ON, disconnect the X2 harness connector at the K84 Keyless Entry Control Module.
  2. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    2. 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, verify the fuse is good and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF, remove the test lamp.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K84 Keyless Entry Control Module.
    • If the test lamp illuminates 
  3. Ignition OFF, connect the X2 harness connector at the K84 Keyless Entry Control Module and disconnect the X3 harness connector at the K9 Body Control Module.
  4. Test for less than 1 V between the ignition circuit terminal 6 and ground.
    • If 1 V or greater 

      Repair the short to voltage on the circuit.

    • If less than 1 V 
  5. Ignition ON.
  6. Verify a test lamp illuminates between the ignition circuit terminal 6 and ground.
    • If the test lamp does not illuminate 
    1. Ignition OFF, remove the test lamp.
    2. Test for infinite resistance between the ignition 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 ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K84 Keyless Entry Control Module.
    • If the test lamp illuminates 
  7. Ignition OFF, remove the test lamp, connect the X3 harness connector at the K9 Body Control Module.
  8. Ignition OFF and all vehicle systems OFF, disconnect the KR73 Ignition Main and KR146 Exhaust Flow Control Valve Relays. It may take up to 2 min for all vehicle systems to power down.
  9. Test for less than 10 Ω between the ground circuit terminals listed below and ground.
    • KR73 Ignition Main Relay - Ground circuit terminal 86
    • KR146 Exhaust Flow Control Valve Relay - Ground circuit terminal 86
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  10. Connect a test lamp between the control circuit terminals listed and the ground.
    • KR73 Ignition Main Relay - Control circuit terminal 85
    • KR146 Exhaust Flow Control Valve Relay - Control circuit terminal 85
  11. Ignition ON.
  12. Verify the test lamp turns ON and OFF when commanding the Run/Crank relay On and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the control 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 control 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 Body Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  13. Test or replace the appropriate KR73 Ignition Main Relay or KR146 Exhaust Flow Control Valve Relay.
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