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Home >> Buick >> 2013 >> Encore Base, AWD >> Repair and Diagnosis >> Engine Mechanical >> Cooling System (Mechanical) >> Engine Cooling System >> Diagnostic Information and Procedures >> DTC P0597-P0599 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the E41 Engine Coolant Thermostat Heater, Ignition ON.
  2. Verify that a test lamp illuminates between the ignition circuit terminal 2 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 ignition 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 not open 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 in the circuit.
      • If infinite resistance, test all the components connected to fuse and replace as necessary.
    • If the test lamp illuminates 
  3. Verify that a test lamp does not illuminate between the ignition circuit terminal 2 and the control circuit terminal 1.
    • If the test lamp illuminates 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine 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, replace the K20 Engine Control Module.
      • If the test lamp does not illuminate 
  4. Remove the test lamp, command the E41 Engine Coolant Thermostat Heater ON with a scan tool.
  5. Verify the scan tool E41 Engine Coolant Thermostat Heater Control Circuit High Voltage Test Status parameter displays OK.
    • If OK is not displayed 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine 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 K20 Engine Control Module.
    • If OK is displayed 
  6. Install a 3 A fused jumper wire between the control circuit terminal 1 and the ignition circuit terminal 2.
  7. Verify the scan tool Engine Coolant Thermostat Heater Circuit High Voltage Test Status parameter is displaying Malfunction when commanding the E41 Engine Coolant Thermostat Heater ON with a scan tool.
    • If Malfunction is not displayed 
    1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module.
    2. 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 K20 Engine Control Module.
    • If Malfunction is displayed 
  8. Test or replace the E41 Engine Coolant Thermostat Heater.
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