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Home >> Nissan-Datsun >> 2021 >> NV2500 HD S >> Repair and Diagnosis >> External Pages >> Different car >> Section 217 (Engine Control System (DTC/Circuit Diagnosis) (CUMMINS 5.0L) (6 Of 6)) >> DTC/Circuit Diagnosis >> DTC P249E-00: Closed Loop REDUCTANT Injection Flow Too High >> Diagnosis Procedure

Diagnosis Procedure

WARNING: This page is about a different car, the 2018 Nissan Titan XD. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK DTC PRIORITY 
    1. Turn ignition switch ON.
    2. Using CONSULT, check for other "ENGINE" diagnostic trouble codes.
    3. Look for DEF dosing, NOx sensor, SCR temperature, or EGR related DTCs, and perform the confirmation procedure (diagnosis procedure) for these other DTCs first.

    Is applicable DTC detected?

    YES

    Refer to DTC Index .

    NO

    GO TO 2 .

  2. CHECK DEF QUALITY 
    1. Turn ignition switch OFF.
    2. Check the DEF quality by visually inspecting the DEF in the tank for signs of debris or contamination.
    3. Using a refractometer [SST: J-54466], measure the concentration of the DEF in the tank.

    Is DEF free from contamination and concentration within 32.5 ± 1.5 %?

    YES

    GO TO 3 .

    NO

    Drain the DEF tank, rinse with water, and refill with pure DEF.

  3. PERFORM DEF DOSING UNIT OVERRIDE TEST 
    1. Remove the after treatment DEF dosing valve from the decomposition tube.
    2. Place the DEF dosing valve in a measuring container having greater than a 1.5 liter [50 oz] capacity.
    3. Turn ignition switch ON.
    4. Using CONSULT, access "ENGINE" and select "DEF Dosing Unit Override Test" active test.

    Did the DEF dosing unit operate according to specifications?

    YES

    GO TO 4 .

    NO

    • Replace the DEF supply pump assembly. Refer to Exploded View .
    • GO TO 4 .
  4. PERFORM SCR PERFORMANCE TEST 
    1. Connect all components and harness connectors.
    2. Start the engine.
    3. Using CONSULT, access "ENGINE" and select "SCR Performance Test" active test.

    Did the SCR performance test complete?

    YES

    GO TO 6 .

    NO

    GO TO 5 .

  5. CHECK DEF DEPOSITS IN THE DECOMPOSITION TUBE 
    1. Turn ignition switch OFF (do not operate the engine).
    2. Inspect the decomposition tube for deposits.
    3. Remove the decomposition tube from the vehicle.
    4. Inspect for excessive DEF deposits.

    Are excessive DEF deposits found inside the decomposition tube?

    YES

    • Clean and install the decomposition tube.
    • GO TO 6 .

    NO

    • Repeat the SCR Performance Test again.
    • GO TO 6 .
  6. CHECK THE STATUS OF THE SCR CATALYST OUTLET NOX SENSOR TEST 
    1. Stop the engine.
    2. Turn ignition switch ON.
    3. With CONSULT, check the results of the SCR Performance Test.
    4. Check the status of the SCR Catalyst Outlet NOx Sensor Test portion of the SCR Performance Test.

    Did SCR catalyst outlet NOx sensor test pass?

    YES

    GO TO 7 .

    NO

    • An in-range malfunction has been detected in the after treatment outlet NOx sensor. Replace the after treatment outlet NOx sensor. Refer to Removal and Installation .
    • GO TO 8 .
  7. CHECK THE STATUS OF THE SCR CATALYST TEST 
    1. With CONSULT, check the results of the SCR Performance Test.
    2. Check the result of the SCR Performance Test.

    Did SCR catalyst test pass?

    YES

    GO TO 8 .

    NO

    • A malfunctioning SCR catalyst has been detected. Replace the after treatment SCR catalyst. Refer to Removal and Installation .
    • GO TO 8 .
  8. ERASE CURRENT DTC 
    1. Connect all harness connectors.
    2. Turn ignition switch ON.
    3. Using CONSULT, erase "ENGINE" diagnostic trouble codes.
    4. Operate the engine within the "Conditions for setting the DTC".
    5. Check for ENGINE diagnostic trouble codes.

    Is P249E-00 DTC current?

    YES

    Return to Diagnosis Procedure. Refer to DTC Description .

    NO

    Repair complete.

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