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Home >> Chevrolet >> 2015 >> Cruze LT, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 14 (Engine Controls And Fuel - 2.0L (LUZ) Diesel - DTC P2122 To DTC P2689 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P20EE, P249D, P249E or P2BAA: NOx Catalyst Efficiency/Closed Loop Reductant >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different variant/trim than selected.
  1. Ignition On.
  2. Verify DTCs P0101, P0191, P0400, P0401, P0402, P0420, P1043, P1044, P1048, P1049, P11CB, P11CC, P11DB, P11DC, P140B, P140C, P202E, P2047, P2048, P2049, P204B, P204C, P204D, P204F, P205B, P205C, P025D, P208A, P208B, P208D, P20A0, P20A2, P20A3, P20E8, P20E9, P2200, P2201, P2202, P2203, P2205, P2209, P229E, P229F, P22A0, P22A1, P22A3, P22A7, P2413, PC29D or PC29E are not set.
    • If none of the DTCs are set 
  3. Verify none of the conditions listed below do not exist with the diesel oxidizing catalyst (DOC) or NOx sensors, SCR system and DPF:
    • Physical damage or alterations
    • Internal rattles caused by a damaged catalyst substrate
    • Exhaust system leaks-Refer to Exhaust Leakage .
    • Loose B195 NOx sensors or B131 Exhaust Gas Temperature sensors
    • If a condition is exists 

      Repair as necessary.

    • If no condition exists 
  4. Verify the reductant is not contaminated. Refer to Contaminants-in-Diesel Exhaust Fluid Diagnosis .
    • If contaminated 

      Repair as necessary.

    • If not contaminated 
  5. Verify the fuel is not contaminated or the fuel quality is poor-Refer to Contaminants-in-Fuel Diagnosis .
    • If contaminated or poor quality 

      Repair as necessary.

    • If not contaminated or poor quality 
  6. 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.
  7. Ignition On.
  8. 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.
  9. Verify there are no leaks in the reductant lines or injector.
    • If a condition is found 

      Repair as necessary

    • If no condition is found 
  10. Verify the scan tool Reductant Pressure sensor parameter is between 400-650 kPa (58-94 psi).
    NOTE: You may have to allow the reductant pump to build pressure for at least 2 minutes.
    • If not between 400-650 kPa (58-94 psi) 

      Refer to DTC P208B .

    • If between 400-650 kPa (58-94 psi) 
  11. Verify the Reductant Injection Quantity Test  passes when commanded On with a scan tool.
    • If the test does not pass 

      Repair as instructed per the Reductant Injection Quantity Test then continue to the next step.

    • If the test passes 
  12. Verify none of the conditions listed below exist:
    • If a condition exists 

      Repair as necessary.

    • If no condition exists 
  13. Verify the Reductant Fluid Quality Test  passes when commanded On with a scan tool.
    NOTE: The reductant fluid quality test may need to be performed 3 times to complete this step.
    • If the first test failed 
    1. Perform the Diesel Particulate Filter (DPF) Service Regeneration  with a scan tool.
    2. Verify the scan tool EGT Sensor 1 and EGT Sensor 2 are between 250-700°C (482-1292°F) after the EGT temperatures have stabilized.
      • If less than 250°C (482°F) or greater than 700°C (1292°F), verify the conditions listed below do not exist and repair as necessary:
      • If between 250-700°C (482-1292°F)
    3. Verify the scan tool EGT 2 temperature is greater than EGT 1.
      NOTE: The EGT temperatures should stabilize during the service regeneration.
      • If EGT 2 temperature is less than EGT 1 temperature, replace the DOC.
      • If EGT 2 temperature is greater than EGT 1
    4. Idle engine for 15 min.
    5. Ignition Off and all vehicle systems Off. It may take up to 2 min for all vehicle systems to power down.
    6. Drive the vehicle for 25 min.
      WARNING: Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.
      NOTE: Do not turn the ignition off prior to performing the following Reductant Fluid Quality Test.
    7. Repeat the Reductant Fluid Quality Test.
      • If the second test failed 
    8. Ignition Off and all vehicle systems Off. It may take up to 5 min for all vehicle systems to power down. Immediately following the key cycle, repeat the Reductant Fluid Quality Test, for a third time.
      • If the third test failed 
    1. Drive the vehicle and perform a heavy acceleration followed by a zero throttle deceleration.
    2. Verify the scan tool parameters listed below return to less than 5 ppm.
      • NOx Sensor 1 NOx Concentration
      • NOx Sensor 2 NOx Concentration
      • If 5 ppm or greater, replace the appropriate B195 Nitrogen Oxide Sensor.
      • If less than 5 ppm, replace the SCR.
    • If the test passes 
  14. All OK.
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