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HOMESERVICE MANUALSCHEVROLET2019TAHOE LS, 4WD, GAS/ETHANOLREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 95 (ENGINE CONTROLS/FUEL - 1.8L (LUW LWE) - DTC P0010 TO DTC P0420)DIAGNOSTIC INFORMATION AND PROCEDURESDTC P0096 OR P0111CIRCUIT/SYSTEM TESTING
2019 Chevrolet Tahoe LS, 4WD, Gas/Ethanol

Circuit/System Testing

2019 Chevrolet Tahoe LS, 4WD, Gas/EthanolSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2018 Chevrolet Sonic. 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 integrity of the entire air induction system and verify that none of the following conditions exist:
    • A restricted, collapsed, misaligned, or damaged air intake duct
    • An intake manifold leak
    • A MAP sensor seal that is leaking, missing, or damaged
    • 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 component as appropriate.

    • Go to next step: If no condition exists 
  2. 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 B75C Mass Air Flow/Multifunction Intake Air sensor.
  3. Test for less than 2 Ω between the low reference circuit terminal 7 and ground.
    • If 2 Ω or greater 
    1. Ignition OFF, 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.
    • Go to next step: If less than 2 Ω 
  4. Ignition ON, test for 4.8 - 5.2 V between the 5 V reference circuit terminal 2 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.
      • Go to next step: 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 5 V reference 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.
    2. Ignition ON, test for less than 1 V between the 5 V reference 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.
    • Go to next step: If between 4.8 - 5.2 V 
  5. Ignition ON, test for 4.8 - 5.2 V between the signal circuit terminal 8 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.
      • Go to next step: 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.
    2. Ignition ON, 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.
    • Go to next step: If between 4.8 - 5.2 V 
  6. Ignition ON, 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 8 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: 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.
    • Go to next step: If colder than -39°C (-38°F). 
  7. Ignition OFF, install a 3 A fused jumper wire between the signal circuit terminal 8 and the low reference circuit terminal 7.
  8. Verify the scan tool IAT Sensor 1 parameter is warmer than 148°C (298°F).
    • If colder than 148°C (298°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.
      • Go to next step: 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.
    • Go to next step: If warmer than 148°C (298°F). 
  9. Determine if EL-38522-A  Variable Signal Generator or equivalent is available.
    • EL-38522-A, Variable Signal Generator; or equivalent is not available 
    1. Replace the K20 Engine Control Module.
    2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
    3. Verify the DTC does not set.
      • If the DTC sets 

        Refer to step 13.

      • Go to next step: If no DTCs set 
    4. All OK.
    • Go to next step: EL-38522-A, Variable Signal Generator; or equivalent is available 
  10. Ignition OFF, connect the leads of the EL-38522-A  Variable Signal Generator as follows:
    • Red lead to the signal circuit terminal 1 at the harness connector
    • Black leads to ground
    • Battery voltage supply lead to B+
  11. Set the EL-38522-A  Variable Signal Generator to the following specifications.
    • Signal switch to 5 V
    • Duty Cycle switch to 50 % (Normal)
    • Frequency switch to 30 Hz
  12. Ignition ON, verify the scan tool IAT Sensor 2 parameter is between 28 - 32 Hz.
    • If not between 28 - 32 Hz 

      Replace the K20 Engine Control Module.

    • Go to next step: If between 28 - 32 Hz 
  13. Circuits and ECM test OK. Test or replace the appropriate temperature sensor.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.