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Home >> Chevrolet >> 2015 >> Cruze LT, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Engine Controls And Fuel - 2.0L (LUZ) Diesel - DTC P0430 To DTC P2080) >> Diagnostic Information and Procedures >> DTC P208B: Reductant Pump Performance >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Verify the following conditions do not exist:
    • Contaminated diesel exhaust fluid-Refer to Contaminants-in-Diesel Exhaust Fluid Diagnosis .
    • Missing, restricted or leaking reductant components
    • Stuck closed, restricted or plugged Q62 Reductant Purge Valve
    • High resistance in the G33 Reductant Pump or Q62 Reductant Purge Valve circuits
    • Inspect the harness connectors and the ground circuits of the reductant tank for poor connections.
    • If a condition is found 

      Repair as necessary

    • If no condition is found 
  2. Ignition On, command the Reductant System Leak Test On with a scan tool. Allow the pressure to build for at least 2 minutes. The first 60 s the system performs a system purge. Observe the scan tool Reductant Pressure Sensor parameter. The reading should be between 400-650 kPa (58-94 psi) and there should be no leaks in the system.
    NOTE: Exhaust Gas Temperature (EGT) sensor 2 must be less than 200°C (392°F) prior to running the Reductant System Leak Test.
    • If a condition is found 

      Repair as necessary

    • If no condition is found 
  3. Remove the Q61 Emission Reduction Fluid Injector from the exhaust pipe leaving the reductant line and electrical connector connected. Place the injector into a suitable container.
  4. Ignition On, command the Reductant System Leak Test On with a scan tool. Allow the pressure to build for at least 2 minutes. The injector should not leak.
    • If the injector leaks 

      Replace the Q61 Reduction Injector

    • If the injector does not leak 
  5. Ignition Off and all vehicle systems Off, disconnect harness connector at the G33 Reductant Pump Motor. It may take up to 2 minutes for all vehicle systems to power down.
  6. Test for less than 5 Ω between the low reference circuit terminal 4 and ground.
    • If greater than 5 Ω 
    1. Disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2 Ω in the low reference 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 less than 5 Ω 
  7. Test for less than 1 V between the G33 Reductant Pump Motor supply voltage circuit terminal 3 and ground.
    • If greater than 1 V 
    1. Disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 1 V on the supply voltage circuit end to end.
      • If greater than 1 V, repair the short to voltage in the circuit.
      • If less than 1 V, replace the K20 Engine Control Module
    • If less than 1 V 
  8. Ignition On.
  9. Test for battery voltage between the G33 Reductant Pump Motor supply voltage circuit terminal 3 and ground.
    • If less than battery voltage 
    1. Ignition Off, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance in the supply voltage circuit to ground.
      • If less than infinite resistance, repair the short to ground in the circuit.
      • If infinite resistance
    1. Test for less than 2 Ω in the supply voltage 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 battery voltage is present 
  10. Test for 2.5-4.5 V between the G33 Reductant Pump Motor control circuit terminal 5 and ground.
    • If less than 2.5 V 
    1. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground in the circuit.
      • If infinite resistance
    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 greater than 4.5 V 
    1. Ignition Off, disconnect the harness connector at the K20 Engine Control Module.
    2. Ignition On.
    3. 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 between 2.5-4.5 V 
  11. Connect a test lamp between the G33 Reductant Pump Motor control circuit terminal 5 and the G33 Reductant Pump Motor supply voltage circuit terminal 3.
  12. Verify the test lamp illuminates or flashes when commanding the reductant pump to 80% with a scan tool.
    • If the test lamp does not illuminate or flash 

      Replace the K20 Engine Control Module.

    • If the test lamp does illuminate or flash 
  13. Replace the G33 Reductant Pump.
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