LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 114 (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 car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
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
scientia non olet · About LEMON Manuals