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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 118 (Engine Controls And Fuel - 3.6L (LF4 LGX) - DTC P0685 LGX To DTC P3436 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Charge Air Cooler Coolant Pump Diagnosis >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2016 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the M 10 Charge Air Cooler Coolant Pump harness connector.
  2. Test for less than 2 Ω between the ground circuit terminal 4 and ground.
    • If 2 Ω or greater 
    1. Disconnect the sensor chassis ground.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 2 Ω 
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminals listed below and ground:
    • Charge Air Cooler Coolant Pump circuit terminal 5
    • Charge Air Cooler Coolant Pump circuit terminal 1
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp and remove the fuse for the ignition voltage circuit.
    2. Test for less than 2 Ω in the ignition voltage 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 and remove the fuse for the ignition voltage circuit.
    2. Test for infinite resistance between the ignition voltage circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for greater than 2 Ω between the ignition voltage circuit and ground.
      • If less than 2 Ω, repair the short to ground on the circuit.
      • If greater than 2 Ω, test all the components connected to the circuit and repair or replace as necessary.
    • If a test lamp illuminates 
    4. 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.

  4. Connect a DMM, set on the diode setting, between the Charge Air Cooler Coolant Pump control circuit terminal 3 and ground.
  5. Verify the DMM reading is greater than 2.5 V or displays O.L. with the Charge Air Cooler Coolant Pump 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 X3 at the K20 Engine Control Module.
    3. Test for infinite resistance between the M 10 Charge Air Cooler Coolant Pump circuit terminal 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. 
  6. Command the Charge Air Cooler Coolant Pump ON with a scan tool.
  7. Verify the DMM reading is less than 1 V.
    • If 1 V or greater 
    1. Ignition OFF.
    2. Disconnect the harness connector X3 at the K20 Engine Control Module, ignition ON.
    3. Test for less than 1 V between the M 10 Charge Air Cooler Coolant Pump control circuit terminal 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 M 10 Charge Air Cooler Coolant Pump and the K20 Engine Control Module terminal X3-3.
      • 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 
  8. Replace the M 10 Charge Air Cooler Coolant Pump.
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