SFI SYSTEM (w/o EGR System), Diagnostic DTC:P148F

DTC Code DTC Name
P148F Engine Coolant Pump Over Revolution

DESCRIPTION

The ECM controls the engine water pump assembly by calculating the necessary amount of coolant flow based on engine coolant temperature, engine speed and vehicle speed information. The speed of the engine water pump assembly is controlled steplessly using a duty cycle signal sent from the ECM. This optimal control enhances warm-up performance and reduces cooling losses, thus reducing the specific fuel consumption of the engine. The ECM monitors the speed of the engine water pump assembly and sets a DTC when it determines that the engine water pump assembly rotates excessively based on the fact that the actual speed is higher than the target for a certain amount of time. (However, the engine warning light will not illuminate.)

DTC No. DTC Detection Condition Trouble Area
P148F

When both of the following conditions are met for 5 seconds or more (1 trip detection logic):


  • Engine water pump assembly duty ratio is 85% or more.

  • Actual engine water pump assembly speed has been more than the target by a certain amount.

  • Lack of engine coolant

  • Engine coolant leak

  • Engine water pump assembly

INSPECTION PROCEDURE

Tech Tips


  • DTC P148F may be stored if the engine has continuously run with insufficient engine coolant. If the engine coolant is sufficient and DTC P148F recur when the vehicle is brought to the workshop, confirm whether engine coolant was added after the vehicle had been driven with insufficient engine coolant.

  • Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P148F)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

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

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC P148F is output A
      DTC P148F and other DTCs are output B

      Tech Tips

      If any DTCs other than P148F are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. CHECK RADIATOR RESERVOIR TANK ASSEMBLY (ENGINE COOLANT LEVEL)


    1. Check that the engine coolant level is between the FULL and LOW lines Click here.

      Result
      Result Proceed to
      Engine coolant level is below the LOW line A
      Engine coolant level is above the LOW line B

    B

    CLEAR DTC (DTC P148F) Click here

    A

  3. CHECK FOR ENGINE COOLANT LEAKS


    1. Check the areas around the engine and heater for engine coolant leaks Click here.

      OK
      No leaks.

      Tech Tips

      If the engine oil is cloudy during the engine oil level gauge check, it means that engine coolant has entered the engine lubrication system.


    NG

    REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA Click here

    OK

  4. ADD ENGINE COOLANT


    1. Fill the reservoir tank up to the FULL line with engine coolant.

      Note

      Make sure not to add engine coolant when the engine is hot.


    NEXT

    CLEAR DTC (DTC P148F) Click here

  5. REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA


    1. Repair any engine coolant leaks.

      Tech Tips

      Add engine coolant and perform air bleeding after repair Click here.


    NEXT

  6. CLEAR DTC (DTC P148F)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTC Click here.


    NEXT

  7. INSPECT ENGINE WATER PUMP ASSEMBLY

    Tech Tips

    Perform repair indoors or in a workshop.


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Put the engine in inspection mode (maintenance mode) Click here.

    5. Start the engine.

    6. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp and Elec Water Pump Spd.

      Tech Tips

      Display the Data List diagram.

    7. Idle the engine for about 20 minutes and check Coolant Temp, Elec Water Pump Spd using the tester, and check the cooling fans.

      Result
      Result Proceed to

      Either of the following conditions is met:


      • The engine coolant temperature becomes 95°C (203°F) or higher and the engine water pump assembly performs intermittent operation (5 second pause after 25 second operation).

      • The engine water pump assembly does not start operating even after the engine coolant temperature becomes 95°C (203°F) or higher.*1, *2

      		 A
      The cooling fans start operating after the engine coolant temperature becomes 95°C (203°F) or less and decrease in the engine coolant temperature is observed.*3 B

      Tech Tips


      • *1: Be careful when the cooling fans do not start operating even after the engine coolant temperature becomes 95°C (203°F) or higher because the engine coolant temperature increases rapidly. (Make sure to stop the engine if the engine coolant temperature becomes 105°C (221°F) or higher.)

      • *2: If the ECM voltage is 14 V or higher and the engine water pump assembly is run excessively due to insufficient coolant etc., the water pump motor speed will exceed 5000 rpm. Enter the following menus to check the voltage of the ECM: Powertrain / Engine and ECT / Data List / All Data / Battery Voltage Click here.

      • *3: When the engine is warmed up, the cooling fans operate and the engine coolant temperature will decrease. After the cooling fans begin operating, the engine coolant temperature will stabilize between 88 to 95°C (190 to 203°F).


    B

    END

    A

  8. REPLACE ENGINE WATER PUMP ASSEMBLY


    1. Replace the engine water pump assembly Click here.


    NEXT

  9. ADD ENGINE COOLANT


    1. Fill the reservoir tank up to the FULL line with engine coolant.

      Note

      Make sure not to add engine coolant when the engine is hot.


    NEXT

  10. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    Tech Tips

    Perform repair indoors or in a workshop.


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Put the engine in inspection mode (maintenance mode) Click here.

    6. Start the engine.

    7. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp and Elec Water Pump Spd.

    8. Idle the engine for about 20 minutes and check Coolant Temp, Elec Water Pump Spd using the tester, and check the cooling fans.

      Result
      The cooling fans start operating after the engine coolant temperature becomes 95°C (203°F) or less and decrease in the engine coolant temperature is observed.

    NEXT

    END