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Home >> Chevrolet >> 2018 >> Equinox L >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 17 (Engine Controls And Fuel - 1.6L (LH7) Diesel - Diagnostic Information And Procedures (P205B - P2BAA) And Symptoms) >> Diagnostic Information And Procedures >> DTC P2199: Intake Air Temperature (IAT) Sensor 1-2 Not Plausible >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
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 or collapsed air intake duct
    • An intake manifold leak
    • A misaligned or damaged air intake duct
    • Any water intrusion in the induction system
    • 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 Multifunction Intake Air sensor.
  3. Test for less than 5 Ω between the low reference circuit terminal 3 and ground.
    • If 5 Ω or greater 
    1. Disconnect the harness connector X1 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 5 Ω 
  4. Test for less than 5 Ω between the ground circuit terminal 7 and ground.
    • If 5 Ω or greater 
    1. Ignition Off.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open or high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 5 Ω 
  5. Ignition On.
  6. 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 X1 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, 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 IAT 1 signal circuit terminal 1 and the low reference circuit terminal 3.
  8. Ignition On.
  9. 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 X1 at the K20 Engine Control Module.
    2. Ignition On.
    3. 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
    4. Ignition Off.
    5. 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). 
    10. NOTE:

    The intake air temperature sensor 2 signal circuit is pulled up with low current voltage within the controller. Normally, a voltage can be measured on the circuit with a DMM, but the current will not be high enough to illuminate a test lamp.

  10. Verify the scan tool Intake Air Humidity Sensor parameter is less than 1%.
    • If 1% or greater 
    1. Ignition Off, disconnect the harness connector X3 at the K20 Engine Control Module.
    2. Test for infinite resistance between the IAT 2 signal circuit terminal 8 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K20 Engine Control Module.
    • Go to next step: If less than 1% 
  11. Ignition Off, install a 3 A fused jumper wire between the IAT 2 signal circuit terminal 8 and the low reference circuit terminal 3.
  12. Ignition On.
  13. Verify the scan tool Intake Air Humidity Sensor parameter is greater than 99%.
    • If 99% or less 
      NOTE:

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

    1. Ignition Off, remove the jumper wire and disconnect the harness connector X3 at the K20 Engine Control Module.
    2. Ignition On.
    3. Test for less than 1 V between the IAT 2 signal circuit terminal 8 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V.
    4. Ignition Off.
    5. 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 greater than 99% 
  14. Test or replace the B75C Multifunction Intake Air sensor.
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