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ECD SYSTEM (w/o DPF), Diagnostic DTC:P0191

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DTC Code DTC Name
P0191 Fuel Rail Pressure Sensor Circuit Range / Performance
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DESCRIPTION

The ECM monitors the internal fuel pressure of the common rail using the fuel pressure sensor, and controls the suction control valve to regulate the common rail pressure so that it reaches the target pressure determined by the ECM. The pressure sensor is a semiconductor that varies its electrical resistance when pressure is applied to its silicon chip. This sensor outputs a voltage in proportion to the common rail fuel pressure.

Table 1. P0191
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Idling for 1 second The difference between the main and sub voltage outputs of the fuel pressure sensor is 0.04 V or less, or 1.06 V or higher for 1 second or more (1 trip detection logic).

  • Open or short in fuel pressure sensor circuit

  • Fuel pressure sensor (common rail)

  • ECM
Table 2. Related Data List
DTC No. Data List
P0191

  • Fuel Press

  • Target Common Rail Pressure
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WIRING DIAGRAM

Refer to DTC P0087 (Click here).

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INSPECTION PROCEDURE

Note:

After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).

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PROCEDURE


  1. Click here

    READ VALUE USING INTELLIGENT TESTER (FUEL PRESS AND TARGET COMMON RAIL PRESSURE)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press and Target Common Rail Pressure.

    4. Start the engine.

    5. Check the change in the values for the data list items above when increasing the engine speed from idling to 3000 rpm with no load.

      Table 3. Result
      Result Proceed to

      Fuel Press is always 10000 kPa or less

      or

      Fuel Press is always 200000 kPa or higher

      		 A
      Except above B
      Tip:

      Normally, "Fuel Press" is within 15000 kPa of "Target Common Rail Pressure".


  2. Click here

    CHECK HARNESS AND CONNECTOR (FUEL PRESSURE SENSOR - ECM)


    1. Disconnect the fuel pressure sensor connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      C82-5 (PR) - C90-16 (PCR1) Always Below 1 Ω
      C82-2 (PR2) - C90-2 (PCR2) Always Below 1 Ω
      C82-1 (VCS) - C90-13 (VCS) Always Below 1 Ω
      C82-6 (VC) - C90-14 (VCM) Always Below 1 Ω
      C82-4 (E2) - C90-15 (E2M) Always Below 1 Ω
      C82-3 (E2S) - C90-8 (E2S) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      C82-5 (PR) or C90-16 (PCR1) - Body ground Always 10 kΩ or higher
      C82-2 (PR2) or C90-2 (PCR2) - Body ground Always 10 kΩ or higher
      C82-1 (VCS) or C90-13 (VCS) - Body ground Always 10 kΩ or higher
      C82-6 (VC) or C90-14 (VCM) - Body ground Always 10 kΩ or higher
      C82-4 (E2) or C909-15 (E2M) - Body ground Always 10 kΩ or higher
      C82-3 (E2S) or C90-8 (E2S) - Body ground Always 10 kΩ or higher

    4. Reconnect the fuel pressure sensor connector.

    5. Reconnect the ECM connector.


  3. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.


  4. Click here

    CHECK WHETHER DTC OUTPUT RECURS (DTC P0191)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Clear the DTCs (Click here).

    4. Let the engine idle for 1 second.

    5. Enter the following menus: Powertrain / Engine and ECT / DTC.

    6. Read the DTCs.

      Table 4. Result
      Result Proceed to
      P0191 is output A
      No DTC is output B

  5. Click here

    REPLACE COMMON RAIL


    1. Replace the common rail (Click here).


  6. Click here

    BLEED AIR FROM FUEL SYSTEM


    1. Bleed the air from the fuel system (Click here).


  7. Click here

    CHECK WHETHER DTC OUTPUT RECURS (DTC P0191)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Clear the DTCs (Click here).

    4. Let the engine idle for 1 second.

    5. Enter the following menus: Powertrain / Engine and ECT / DTC.

    6. Read the DTCs.

      Table 5. Result
      Result Proceed to
      P0191 is output A
      No DTC is output B

  8. Click here

    REPLACE ECM


    1. Replace the ECM (Click here).


  9. Click here

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Clear the DTCs (Click here).

    4. Let the engine idle for 1 second.

    5. Enter the following menus: Powertrain / Engine and ECT / DTC.

    6. Confirm that the DTC is not output again.


  10. Click here

    END