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Home >> Chevrolet >> 2017 >> Malibu LS >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 29 (Engine Controls And Fuel - 1.8L (LKN) - DTC P0446 To DTC P2635 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P2418-P2420: Evaporative Emission (EVAP) System Leak Detection Pump Switching Valve Control Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Vehicle OFF, disconnect the harness connector at the Q63 Evaporative Emission System Leak Detection Pump Assembly, vehicle in Service Mode.
  2. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Vehicle 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. Vehicle 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 this voltage circuit for a short and replace as necessary.
    • If the test lamp illuminates 
  3. Verify that a test lamp does not illuminate between the B+ circuit terminal 5 and the control circuit terminal 1.
    • If the test lamp illuminates 
    1. Vehicle 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.
    • If the test lamp does not illuminate 
  4. Remove the test lamp.
  5. Verify the scan tool EVAP Leak Detection Pump Switching Valve Output Circuit High Voltage Test Status parameter displays OK when commanding the EVAP Leak Detection Pump Switching Valve On with a scan tool.
    • If OK is not displayed 
    1. Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module, vehicle 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.
    • If OK is displayed 
  6. Install a 3 A fused jumper wire between the control circuit terminal 1 and the B+ circuit terminal 5.
  7. Verify the scan tool EVAP Leak Detection Pump Switching Valve Control Circuit High Voltage Test Status parameter is Malfunction when commanding the EVAP Leak Detection Pump Switching Valve On with a scan tool.
    • If Malfunction is not displayed 
    1. Vehicle 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.
    • If Malfunction is displayed 
  8. Test or replace the Q63 Evaporative Emission System Leak Detection Pump Assembly.
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