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Home >> Chevrolet >> 2015 >> Cruze LT, Automatic Trans >> Repair and Diagnosis >> Engine Mechanical >> Cooling System (Mechanical) >> Engine Cooling System >> Diagnostic Information and Procedures >> DTC P0480, P0691 or P0692: Cooling Fan Speed Output Circuit (LUZ) >> Circuit/System Testing

Circuit/System Testing

  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 1 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.
    • If the test lamp illuminates 
  3. Ignition ON.
  4. Test for 3-4 V between the cooling fan speed output control circuit terminal 3 and ground.
    NOTE: The cooling fan speed output circuit is pulled-up to a voltage within the ECM, 2-3 volts on the output circuit is normal.
    • If 3 V or less 
    1. Ignition OFF and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
    2. Disconnect the harness connector X1 at the K20 Engine Control Module.
    3. Test for infinite resistance between the G10 Cooling Fan Motor control circuit terminal 3 and ground.
      • If less than infinite resistance, repair the short to ground in the circuit.
      • If infinite resistance.
    4. 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, test or replace the K20 Engine Control Module.
    • If 4 V or greater 
    1. Ignition OFF.
    2. Disconnect the harness connector X1 at the K20 Engine Control Module, ignition ON.
    3. Test for less than 1 V between the G10 Cooling Fan Motor control circuit terminal 3 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, test or replace the K20 Engine Control Module.
    4. Ignition OFF and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
    5. Test for less than 2 Ω in the 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.
    • If between 3-4 V 
  5. Connect a 3 A fused jumper wire in the G10 Cooling Fan Motor control circuit terminal 3 and ground.
  6. Verify the scan tool Cooling Fan Output Circuit Low Voltage Test Status displays Malfunction.
    • If not Malfunction 

      Test or replace the K20 Engine Control Module.

    • If Malfunction 
  7. Test or replace the G10 Cooling Fan Motor.
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