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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 92 (Engine Controls And Fuel - 2.8L (LWN) Diesel - Diagnostic Information And Procedures (1 Of 3)) >> Diagnostic Information and Procedures >> DTC P02E0, P02E2, P02E3, P02EB, P122B, P122C, or P1425 >> 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.
  1. Ignition/Vehicle - Off
  2. Verify the following conditions do not exist: Blade @ Q20 Intake Air Flow Valve
      WARNING:

      Turn OFF the ignition before inserting fingers into the throttle bore. Unexpected movement of the throttle blade could cause personal injury.

    • Binding or Sticking @ Open/Close - Position
    • Closed @ Engine Off
    • Coking/Debris / Dirty / Visible Damage
    • Open/Close - Without spring pressure
    • If a condition exists 

      Replace the component: Q20 Intake Air Flow Valve

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

    Disconnecting the component electrical connector causes additional DTCs to set.

  3. Disconnect the electrical connector: Q20 Intake Air Flow Valve
  4. Ignition - On / Vehicle - In Service Mode
  5. Test for 1. 5 to 2. 5 V between the test points: Control circuit terminal 1 & Ground
    • If less than 1. 5 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X2 @ K20 Engine Control Module
    3. Test for infinite resistance between the test points: Control 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 infinite resistance between the test points: Control circuit terminal 1 & Control circuit terminal 2
      • If less than infinite resistance - Repair the short between the circuits.
      • Go to next step: If infinite resistance
    5. Test for less than 2 ohms between the test points: Control 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 2. 5 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X2 @ K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control 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 1. 5 and 2. 5 V 
  6. Verify a test lamp does not turn On between the test points: Control circuit terminal 2 & B+
    • If the test lamp turns On 
    1. Ignition/Vehicle - Off Remove - Test Lamp
    2. Disconnect the electrical connector: X2 @ K20 Engine Control Module
    3. Test for infinite resistance between the test points: Control 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 the test lamp does not turn On 
  7. Verify a test lamp does not turn On between the test points: Control circuit terminal 2 & Ground
    • If the test lamp turns On 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X2 @ K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 2 @ 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 the test lamp does not turn On 
  8. Test for 1. 5 to 2. 5 V between the test points: Control circuit terminal 1 & Control circuit terminal 2
    • If not between 1. 5 and 2. 5 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X2 @ K20 Engine Control Module
    3. Test for less than 2 ohms between the test points: Control 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 between 1. 5 and 2. 5 V 
  9. Test or replace the component: Q20 Intake Air Flow Valve
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