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Home >> Cadillac >> 2018 >> Escalade Base, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 11 (Engine Controls And Fuel - 6.0L (L96) - DTC P0351 To DTC P2636 And Diagnostic Information And Procedures) >> Diagnostic Information And Procedures >> DTC P0449, P0498 Or P0499: Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2018 Chevrolet Suburban 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the Q13 Evaporative Emission Vent Solenoid Valve, Ignition ON,
  2. Verify that a test lamp illuminates between the B+ circuit terminal A or 2 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF, remove the test lamp.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, test all components connected to the B+ circuit for a short and replace as necessary.
    • Go to next step: If the test lamp illuminates 
  3. Verify that a test lamp does not illuminate between the B+ circuit terminal A or 2 and the control circuit terminal B or 1.
    • If the test lamp illuminates 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K20 Engine Control Module.
    • Go to next step: If the test lamp does not illuminate 
  4. Remove the test lamp.
  5. Verify the scan tool EVAP Vent Solenoid Valve Control Circuit High Voltage Test Status parameter is OK when commanding the EVAP Vent Solenoid Valve to ON (Not Venting) with a scan tool.
    • If OK is not displayed 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, Ignition ON.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K20 Engine Control Module.
    • Go to next step: If OK is displayed 
  6. Install a 3 A fused jumper wire between the control circuit terminal B or 1 and the B+ circuit terminal A or 2.
  7. Verify the scan tool EVAP Vent Solenoid Valve Control Circuit High Voltage Test Status parameter is Malfunction when commanding the EVAP Vent Solenoid Valve to ON (Not Venting) with a scan tool.
    • If Malfunction is not displayed 
    1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω replace the K20 Engine Control Module.
    • Go to next step: If Malfunction is displayed 
  8. Test or replace the Q13 Evaporative Emission Vent Solenoid Valve.
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