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Home >> Cadillac >> 2018 >> CT6 Plug-In >> Repair and Diagnosis >> Hybrid/Electric Powertrain >> Cooling Systems >> Hybrid/EV System Heating And Cooling System >> Diagnostic Information and Procedures >> DTC P19FD-P19FF >> Circuit/System Testing

Circuit/System Testing

  1. Vehicle OFF, disconnect the harness connector at the G37 Hybrid/EV Battery Pack Coolant Pump.
  2. Test for less than 5 Ω between the ground circuit terminal 4 and ground.
    • If 5 Ω or greater 

      Repair the open/high resistance on the ground circuit.

    • Go to next step: If less than 5 Ω 
  3. Vehicle in Service Mode.
  4. Test for B+ between the B+ circuit terminal 5 and the ground circuit terminal 4.
    • If less than B+ 
    1. Vehicle OFF, test for infinite resistance between the B+ circuit terminal 5 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    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 and the fuse is blown, replace the G37 Hybrid/EV Battery Pack Coolant Pump.
    • Go to next step: If B+ 
  5. Connect a test lamp between the enable circuit terminal 1 and the ground circuit terminal 4.
  6. Vehicle OFF, charge cord removed. Verify the test lamp is OFF.
    • If the test lamp is ON 
    1. Vehicle OFF, disconnect the X2 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.
    2. Test for less than 1 V between the pump enable circuit terminal and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K114B hybrid/EV powertrain control module 2.
    • If the test lamp is OFF 
  7. Vehicle ON. Verify the test lamp illuminates. Command the Hybrid Battery Pack Coolant Pump ON (20 - 90%) with a scan tool if necessary.
    • If the test lamp is OFF 
    1. Vehicle OFF, disconnect the X2 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.
    2. Test for infinite resistance between the pump enable circuit and 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 in the pump enable circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K114B Hybrid/EV Powertrain Control Module 2.
    • Go to next step: If the test lamp is ON 
  8. Connect a test lamp between the control circuit terminal 3 and the B+ circuit terminal 5.
  9. Verify that a test lamp changes illumination between bright (20%) and dim (90%) when commanding the Hybrid Battery Pack Coolant Pump ON between 20% and 90% with a scan tool.
    • If the test lamp is always dim or does not illuminate 
    1. Vehicle OFF, disconnect the X2 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.
    2. Test for less than 1 V between the control circuit terminal and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    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 K114B Hybrid/EV Powertrain Control Module 2.
    • If the test lamp is always bright 
    1. Vehicle OFF, disconnect the X2 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.
    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, replace the K114B Hybrid/EV Powertrain Control Module 2.
    • Go to next step: The test lamp changes illumination between bright (20%) and dim (90%) 
  10. Remove the test lamp.
  11. Verify the scan tool Hybrid Battery Pack Coolant Pump Feedback parameter is 0%.
    • If greater than 0% 
    1. Vehicle OFF, disconnect the X2 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.
    2. Test for infinite resistance between the feedback circuit terminal 2 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance, replace the K114B Hybrid/EV Powertrain Control Module 2.
    • Go to next step: If 0% 
  12. Install a 3 A fused jumper wire between the feedback circuit terminal 2 and the ground circuit terminal 4.
  13. Verify the scan tool Hybrid Battery Pack Coolant Pump Feedback parameter is greater than 90%.
    • If 90% or less 
    1. Vehicle OFF, disconnect the X2 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.
    2. Test for less than 1 V between the feedback circuit terminal and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    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 K114B Hybrid/EV Powertrain Control Module 2.
    • Go to next step: If greater than 90% 
  14. Replace the G37 Hybrid/EV Battery Pack Coolant Pump.
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