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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 20 (Engine Controls And Fuel - 4.3L (LV1) - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC P0106, P0107, or P0108 >> 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. Ignition/Vehicle & All vehicle systems - Off
  2. Verify the following conditions do not exist :
    • B75C Multifunction Intake Air Sensor - Contamination of the measuring element/Water intrusion/Cracked/Loose Clamps/Visible Damage
    • Q38 Throttle Body - Loose Clamps/Visible Damage
    • Air Cleaner Element - Dirty/Restricted
    • Exhaust System - Leaking/Missing components/Restricted
    • Intake Air Duct & Intake Manifold - Cracked/Loose Clamps/Restricted/Visible Damage - Refer to : Intake Manifold Cleaning and Inspection
    • O-Ring @ B74 Manifold Absolute Pressure Sensor/Leaking/Missing/Visible Damage
    • Positive Crankcase Ventilation System - Leaking/Incorrect connection/Restricted
    • Vacuum Hoses - Kinked/Leaking/Incorrect connection/Restricted
    • Vacuum leak @ Engine/Intake Manifold/Q38 Throttle Body
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step : If no condition exists 
  3. Test or inspect for the following : - An engine mechanical condition
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step : If no condition exists 
    4. NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low Reference circuit continuity test can be performed.

  5. Disconnect the electrical connector : B74 Manifold Absolute Pressure Sensor
  6. Test for less than 5 ohms between the test points : Low Reference circuit terminal 2 & Ground
    • If 5 ohms or greater 
    1. Disconnect the electrical connector : X2 @ K20 Engine Control Module
    2. Test for less than 2 ohms between the test points : Low Reference circuit terminal 2 @ 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 less than 5 ohms 
  7. Ignition - On / Vehicle - In Service Mode
  8. Test for 4.8 to 5.2 V between the test points : 5 V Reference circuit terminal 1 & Low Reference circuit terminal 2
    • If less than 4.8 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector : X2 @ K20 Engine Control Module
    3. Test for infinite resistance between the test points : 5 V Reference circuit terminal 1 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step : If infinite resistance
    4. Test for less than 2 ohms between the test points : 5 V Reference 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
    • If greater than 5.2 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector : K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points : 5 V Reference circuit terminal 1 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component : K20 Engine Control Module
    • Go to next step : If between 4.8 and 5.2 V 
  9. Verify the scan tool parameter : MAP Sensor = Less than 0.5 V
    • If 0.5 V or greater 
    1. Ignition/Vehicle - Off
    2. Disconnect the 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 3 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component : K20 Engine Control Module
    • Go to next step : If less than 0.5 V 
  10. Connect a 3 A fused jumper wire between the test points : Signal circuit terminal 3 & 5 V Reference circuit terminal 1
  11. Verify the scan tool parameter : MAP Sensor = Greater than 4.5 V
    • If 4.5 V or less 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector : K20 Engine Control Module
    3. Test for infinite resistance between the test points : Signal circuit terminal 3 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step : If infinite resistance
    4. Test for less than 2 ohms between the test points : Signal circuit terminal 3 @ 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 greater than 4.5 V 
  12. Test or replace the component : B74 Manifold Absolute Pressure Sensor
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