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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 174 (Engine Cooling System) >> Diagnostic Information and Procedures >> DTC P0480, P0691, or P0692: Cooling Fan Speed (LGX with Y4Q) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector X1 at the K22 Cooling Fan Control Module, 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 K22 Cooling Fan Control Module.
    • If the test lamp illuminates 
    3. 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.

  3. Connect a DMM, set on the diode setting, between the control circuit terminal X1-3 and ground.
  4. Verify the DMM reading is greater than 2.5 V or displays O.L. with the cooling fan commanded OFF.
    • If 2.5 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 K22 Cooling Fan Control Module control circuit terminal X1-3 and ground.
      • If less than infinite resistance, repair the short to ground in the circuit.
      • If infinite resistance, replace the K20 Engine Control Module.
    • If greater than 2.5 V or displays O.L. 
  5. Command the cooling fan ON with a scan tool using Command State 5.
  6. Verify the DMM reading is less than 1 V.
    • If 1 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 K22 Cooling Fan Control Module control circuit terminal X1-3 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V.
    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 circuit between the K22 Cooling Fan Control Module terminal X1-3 and the K20 Engine Control Module terminal X1-17.
      • If 2 Ω or greater, repair the open in the circuit.
      • If less than 2 Ω, replace the K20 Engine Control Module.
    • If less than 1 V 
  7. Replace the K22 Cooling Fan Control Module.
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