ECD SYSTEM (w/o DPF), Diagnostic DTC:P1238

DTC Code DTC Name
P1238 Injector Malfunction

DESCRIPTION

Tech Tips


  • For more information on the injector and the common rail system Click here.

  • If DTC P1238 is present, refer to the Diagnostic Trouble Codes (DTCs) Table for Common Rail System Click here.

The ECM detects combustion deterioration for a specific cylinder.

A01BBKEE02

Tech Tips


  • The cylinder, which has the compensation value for Injection Feedback Val #1, #2, #3 and #4 that varies from other cylinders, may be malfunctioning.

  • If DTC P0093 (fuel leaks from high-pressure area) is set simultaneously, a leakage malfunction of the cylinder has probably occurred.

  • If DTC P0200 (open or short in the EDU or injector circuit) is set simultaneously, there is probably a faulty circuit located between the ECM and the injector including the EDU.

  • If only DTC P1238 (injector malfunction) is present, an injector mechanical malfunction or insufficient compression (valve clearance etc.) has probably occurred. An open or short malfunction of the ECM, EDU or injector circuit is unlikely.

  • The solenoid valve of the injector is the same type as that of the pressure discharge valve.

DTC No. DTC Detection Condition Main Trouble Area Related Trouble Area
P1238 Engine speed fluctuation is large when idling (2 trip detection logic)

  • Injector

  • EDU (P0200 set simultaneously)

  • Open or short in engine wire harness (P0200 set simultaneously)

  • Connector connection (P0200 set simultaneously)

  • Compression pressure

  • Valve clearance

  • Valve timing

  • Fuel with low cetane number used

  • ECM

Tech Tips

After confirming DTC P1238, check the internal fuel pressure in Powertrain / Engine / Data List / Fuel Press using an intelligent tester.

Reference
Engine Speed Fuel Pressure (MPa)
Idling Approximately 30 to 40
3,000 rpm (No engine load) Approximately 85 to 105

MONITOR DESCRIPTION

P1238 (Injection malfunction, except open or short in injector circuit):

This DTC will be set if the engine speed fluctuation between each cylinder is large. The ECM monitors changes in the crankshaft rotation speed using the crankshaft position sensor in order to detect improper combustion. The camshaft position sensor also plays a role in determining which cylinder has the problem. The fluctuation counter increments when irregular crankshaft rotation speed variation exceeds the threshold with the engine idling. Therefore, if any one of the cylinders is operating poorly (rough idle), the ECM sets this DTC.

WIRING DIAGRAM

Refer to DTC P0200 Click here.

INSPECTION PROCEDURE

Tech Tips


  • If DTCs other than P1238 are present simultaneously, first troubleshoot those DTCs.

  • Read freeze frame data using an intelligent tester. Freeze frame data record the engine condition when malfunctions are detected. 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 P1238)


    1. Connect an intelligent tester to the DLC3.

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

    3. Select the following menu items: Powertrain / Engine / DTC.

    4. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      P1238 A
      P1238 and other DTCs B

      Tech Tips


      • If any DTCs other than P1238 are output, troubleshoot those DTCs first.

      • If any DTCs other than P1238 are not output, check the fuel condition before proceeding to next step.


    B

    GO TO DTC CHART

    A

  2. CHECK HARNESS AND CONNECTOR (ENGINE WIRE HARNESS)

    Tech Tips

    Check the wire harness and connector connections.

    OK
    The wire harness and connectors have been connected securely and there are good connections

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. READ VALUE USING INTELLIGENT TESTER (COMPENSATION OF INJECTION VOLUME BETWEEN CYLINDERS)


    1. Connect an intelligent tester to the DLC3.

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

    3. Select the following menu items: Powertrain / Engine / Data List / Injection Feedback Val #1, #2, #3 and #4.

    4. Read the value.

      Standard
      The compensatory injection volume is between -4.9 mm3/st and 4.9 mm3/st

      Tech Tips


      • If the injection is malfunctioning, the compensatory injection volume remains at -5.0 mm3/st or 5.0 mm3/st.

      • The compensatory injection volume is usually between -3.0 mm3/st and 3.0 mm3/st.

    5. Any cylinders that have a higher compensatory injection volume than shown above are considered to be faulty. Use the following steps to inspect and repair the cylinders.

      Result
      Result Proceed To
      Faulty cylinder is not identified A
      Faulty cylinder is identified B

    B

    CHECK CYLINDER COMPRESSION PRESSURE OF MALFUNCTIONING CYLINDER Click here

    A

  4. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (INJECTION CUT FOR IDENTIFYING MALFUNCTION CYLINDER)


    1. Connect an intelligent tester to the DLC3.

    2. Start the engine and turn the tester ON.

    3. Select the following menu items: Powertrain / Engine / Active Test / Control the Cylinder #1 to #4 Fuel Cut.

    4. Check the four cylinders in sequence to identify a faulty cylinder by performing the power-balance inspection.

      Tech Tips

      If the engine idle does not change when an injector is disabled, the cylinder being tested is malfunctioning.


    NEXT

  5. CHECK CYLINDER COMPRESSION PRESSURE OF MALFUNCTIONING CYLINDER


    1. Check the cylinder compression pressure Click here.

      Standard
      2,000 kPa (20.39 kgf/cm2, 290 psi)
      Minimum pressure
      1,630 kPa (16.62 kgf/cm2, 236.4 psi)
      Difference between each cylinder
      500 kPa (5.0 kgf/cm2, 71 psi)

    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

  6. CHECK VALVE CLEARANCE OF MALFUNCTIONING CYLINDER

    Tech Tips

    Refer to Valve Clearance Adjustment procedure Click here.

    OK
    The valve clearance is within the standard range

    NG

    ADJUST VALVE CLEARANCE

    NG

  7. CHECK WHETHER DTC OUTPUT RECURS (DTC P1238)


    1. Connect an intelligent tester to the DLC3.

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

    3. Select the following menu items: Powertrain / Engine / DTC / Clear.

    4. Clear DTCs.

      Tech Tips

      Before clearing DTCs, save the data stored in the ECM memory if necessary.

    5. Switch the ECM from normal mode to check mode Click here.

    6. Start the engine and warm it up.

    7. Allow the engine to idle for 60 seconds or more.

    8. Select the following menu items: Powertrain / Engine / DTC.

    9. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      P1238 A
      No output B

    B

    CHECK FOR INTERMITTENT PROBLEMS

    A

  8. REPLACE INJECTOR

    Replace injector Click here.


    NEXT

  9. CHECK WHETHER DTC OUTPUT RECURS (DTC P1238)

    Tech Tips

    After clearing the DTC, let the engine idle for 10 minutes after warming up, and then confirm that DTC P1238 is not present again.


    NEXT

    END