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Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Engine Controls And Fuel - 2.0L (LSY) - Diagnostic Information And Procedures (2 Of 2)) >> Diagnostic Information and Procedures >> DTC P0449, P0498, or P0499 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: Q13 Evaporative Emission Vent Solenoid Valve
  3. Ignition - On/Vehicle - In Service Mode
  4. Verify a test lamp turns On between the test points: B+ circuit terminal 2/B & 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: B+ circuit terminal 2/B & Output terminal @ 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 & Remove - Test lamp
    2. Test for infinite resistance between the test points: B+ circuit terminal 2/B & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: Q13 Evaporative Emission Vent Solenoid Valve
    • Go to next step: If the test lamp turns On 
  5. Verify a test lamp does not turn On between the test points: Control circuit terminal 1/A & B+
    • If the test lamp turns On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 1/A @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K111 Fuel Pump Driver Control Module
    • Go to next step: If the test lamp does not turn On 
  6. Remove - Test Lamp
  7. Perform the scan tool control function: EVAP Vent Solenoid Valve @ K20 Engine Control Module - Not Venting

    Verify the scan tool parameter: EVAP Vent Solenoid Valve Control Circuit High Voltage Test Status = OK

    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 1/A @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K111 Fuel Pump Driver Control Module
    • Go to next step: If the specified state 
  8. Connect a 3 A fused jumper wire between the test points: Control circuit terminal 1/A & B+ circuit terminal 2/B
  9. Perform the scan tool control function: EVAP Vent Solenoid Valve @ K20 Engine Control Module - Not Venting

    Verify the scan tool parameter: EVAP Vent Solenoid Valve Control Circuit High Voltage Test Status = Malfunction

    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module
    3. Test for less than 2 ohms between the test points: Control circuit terminal 1/A @ 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: K111 Fuel Pump Driver Control Module
    • Go to next step: If the specified state 
  10. Test or replace the component: Q13 Evaporative Emission Vent Solenoid Valve
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