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Home >> Chevrolet >> 2020 >> Malibu LS >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Engine Cooling System) >> Diagnostic Information and Procedures >> DTC P1485-P1487 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor, ignition ON.
  2. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
    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 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, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground in the circuit.
      • If infinite resistance, replace the G10 Cooling Fan Motor.
    • Go to next step: If the test lamp illuminates 
  3. Verify that a test lamp does not illuminate between the B+ circuit terminal 2 and the control circuit terminal 4.
    • If the test lamp illuminates 
    1. Ignition OFF, remove the test lamp, disconnect the X1 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.
    • Go to next step: If the test lamp does not illuminates 
  4. Remove the test lamp,
  5. Verify the scan tool Cooling Fan Control Circuit High Voltage Test Status parameter is OK when Cooling Fan Motor Command is greater than 10% on a scan tool.
    • 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 infinite resistance, replace the K20 Engine Control Module.
    • Go to next step: If OK is displayed 
  6. Install a 3 A fused jumper wire between the control circuit terminal 4 and the B+ circuit terminal 2.
  7. Verify the scan tool Cooling Fan Control Circuit High Voltage Test Status parameter is Malfunction when Cooling Fan Motor Command is greater than 10% on 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 appropriate Cooling Fan control circuit end to end.
      • If 2 Ω or greater, repair the open in the circuit.
      • If less than 2 Ω, replace the K20 Engine Control Module.
    • Go to next step: If Malfunction is displayed 
  8. Replace the G10 Cooling Fan Motor.
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