LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 278 (Engine Controls And Fuel - 3.6L (LGX LF4) - DTC P0117 (LGX) To DTC P0697) >> Diagnostic Information and Procedures >> DTC P026A: Charge Air Cooler (CAC) Low Efficiency >> 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.
NOTE:

You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Check the operation of the charge air cooler coolant pump

    Refer to Charge Air Cooler Coolant Pump Diagnosis for diagnosis.

    • If a condition exists 

      Repair or replace the component as appropriate.

    • If no condition exists 
    2. WARNING:

    To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

    NOTE:

    Make sure the intercooler system is cool and that the pump is not in the ON position.

  2. Verify that the charge air cooling system is at the proper level, has no coolant leaks, and is completely free of air.

    Refer to Charge Air Cooling System Draining and Filling (LF4)

    • If a condition exists 

      Correct as appropriate.

    • If no condition exists 
  3. Check the integrity of the entire air induction system and verify that none of the conditions listed below exist:
    • A binding or sticking condition when opening or closing the by-pass valve and linkage
    • Loose clamps, cracks, or other damage in the air intake duct system
    • A loose or disconnected charge air cooler hose or pipe
    • A restricted or collapsed air intake duct
    • An intake manifold leak
    • A Turbocharger Boost/Intake Air Temperature Sensor 3 seal that is leaking, missing, or damaged
    • A MAP sensor seal that is leaking, missing, or damaged
    • A restricted or collapsed air intake duct
    • A misaligned or damaged air intake duct
    • Any water intrusion in the induction system
    • An Intake Manifold Resonator with a leaking seal, or a cracked or broken housing
    • If a condition exists 

      Repair or replace the component as appropriate.

    • If no condition exists 
  4. Ignition OFF, and all vehicle systems OFF, it may take up to 2 min. for all vehicle systems to power down. Disconnect the harness connector at the B111B Turbocharger Boost/Intake Air Temperature sensor (IAT Sensor 3).
  5. Test for less than 2 Ω between the intake air temperature sensor 3 low reference circuit terminal 3 and ground.
    • If 2 Ω or greater 
    1. Disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2 Ω in the low reference circuit end to end.
      • If 2 Ω or greater, repair the open or high resistance in the circuit.
      • If less than 2 Ω replace the K20 Engine Control Module.
    • If less than 2 Ω 
  6. Ignition ON.
  7. Test for 4.8-5.2 V between the intake air temperature sensor 3 signal circuit terminal 1 and ground.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the signal 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 greater than 5.2 V 
      NOTE:

      If the signal circuit is shorted to a voltage the engine control module or the sensor may be damaged.

    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the signal 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 between 4.8-5.2 V 
  8. Verify the scan tool IAT Sensor 1 parameter is colder than -39°C (-38°F).
    • If warmer than -39°C (-38°F). 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the signal circuit terminal 1 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the signal 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.
  9. Ignition OFF, install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 3, ignition ON.
  10. Verify the scan tool IAT Sensor 3 parameter is warmer than 149°C (300°F).
    • If colder than 149°C (300°F). 
    1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Ignition OFF.
    4. Test for less than 2 Ω in the signal 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 warmer than 149°C (300°F). 
  11. Test or replace the B111B Turbocharger Boost/Intake Air Temperature sensor (IAT Sensor 3).
scientia non olet · About LEMON Manuals