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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 21 (Engine Controls And Fuel - 4.3L (LV1) - Diagnostic Information And Procedures (2 Of 2)) >> Diagnostic Information and Procedures >> DTC P2199 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
NOTE:

Circuit/System Verification must be performed before proceeding with Circuit/System Testing.

  1. Verify the following conditions do not exist :
    • B75C Multifunction Intake Air Sensor - Contamination of the measuring element/Cracked/Visible Damage/Water intrusion
    • Intake Air Duct - Cracked/Incorrect connection/Restricted/Visible Damage
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step : If no condition exists 
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector : B75C Multifunction Intake Air Sensor
  3. Test for less than 5 ohms between the test points : Ground circuit terminal 7 & Ground
    • If 5 ohms or greater 
    1. Disconnect the appropriate ground connection : Chassis Ground
    2. Test for less than 2 ohms between the test points : Ground circuit terminal 7 @ Component harness & The other end of the circuit
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step : If less than 5 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify a test lamp turns On between the test points : Ignition circuit terminal 5 & Ground
    • If the test lamp does not turn On and the circuit fuse is OK 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for less than 2 ohms between the test points : Ignition circuit terminal 5 @ Control module harness & Output terminal @ F43UA Fuse
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not turn On and the circuit fuse is open 
    1. Ignition/Vehicle - Off
    2. Replace the component : F43UA Fuse
    3. Ignition - On / Vehicle - In Service Mode
    4. Verify the fuse does not open.
      • If the fuse opens and there are components connected to the circuit - Disconnect a component and repeat procedure starting at step 5.1 - 5.4
      • If the fuse opens with all components disconnected from the circuit - Repair the short to ground on the circuit.
      • If the fuse does not open after disconnecting a component from the circuit - Replace the component disconnected last.
      • Go to next step : If the fuse does not open with all components connected, except the following component : K20 Engine Control Module
    5. Ignition/Vehicle - Off
    6. Connect the electrical connector : K20 Engine Control Module
    7. Replace the component : F43UA Fuse
    8. Ignition - On / Vehicle - In Service Mode
    9. Verify the fuse does not open.
      • If the fuse is open - Replace the component : K20 Engine Control Module
      • Go to next step : If the fuse does not open.
      10. NOTE:

      It may be necessary to use a scan tool control function to operate a component.

    10. Operate the component : Each component on the circuit - One at a time

      Verify the fuse does not open when any of the components are activated.

      • If the fuse opens - Replace the component that caused the fuse to open when activated.
      • Go to next step : If the fuse does not open.
    11. All OK.
    • Go to next step : If the test lamp turns On 
  6. Verify the scan tool parameter : IAT Sensor 1 = Colder than -39°C (-38°F)
    • If -39°C (-38°F) or warmer 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector : K20 Engine Control Module
    3. Test for infinite resistance between the test points : Signal circuit terminal 1 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component : K20 Engine Control Module
    • Go to next step : If colder than -39°C (-38°F) 
  7. Connect a 3 A fused jumper wire between the test points : Signal circuit terminal 1 & Low Reference circuit terminal 3
  8. Verify the scan tool parameter : IAT Sensor 1 = Warmer than 149°C (300°F)
    • If 149°C (300°F) or colder 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the appropriate electrical connector : K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points : Signal circuit terminal 1 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step : If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points : Signal circuit terminal 1 @ Component harness & The other end of the circuit @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component : K20 Engine Control Module
    • Go to next step : If warmer than 149°C (300°F) 
  9. Verify the scan tool parameter : Intake Air Humidity Sensor = Less than 1%
    • If 1% or greater 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector : K20 Engine Control Module
    3. Test for infinite resistance between the test points : Signal circuit terminal 8 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component : K20 Engine Control Module
    • Go to next step : If less than 1% 
  10. Ignition/Vehicle - Off
  11. Connect a 3 A fused jumper wire between the test points : Signal circuit terminal 8 @ Component harness & Low Reference circuit terminal 3
  12. Ignition - On / Vehicle - In Service Mode
  13. Verify the scan tool parameter : Intake Air Humidity Sensor = Greater than 99%
    • If less than 99% 
      NOTE:

      Internal control module or component damage may occur if the circuit shorts to B+.

    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the appropriate electrical connector : K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points : Signal circuit terminal 8 & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step : If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points : Signal circuit terminal 8 & The other end of the circuit
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component : K20 Engine Control Module
    • If greater than 99% 
  14. Test or replace the component : B75C Multifunction Intake Air Sensor
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