ECD SYSTEM, Diagnostic DTC:P1238

DTC Code DTC Name
P1238 Injector Malfunction

DESCRIPTION

Tech Tips


  • For more information on the injector and the common rail system, refer to the following procedures Click here.

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

The ECM detects combustion deterioration for a specific cylinder.

The actuator in the injector, which operates the nozzle needle, is a piezo type to allow high-speed operation. This high speed injector uses two stage injection to reduce combustion noise, and provide high power output.

An injector consists of a nozzle needle, two pistons, a three-way valve and a piezo actuator.

An injector compensation value and Quick Response (QR) code containing encoded characteristics of the individual injector are printed on each injector.

The injector compensation value and QR code contain various information regarding the injector, such as model code, and injection volume correction.

The ECM detects combustion deterioration for each specific cylinder.

A01KH5SE03

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 in high-pressure area) is present simultaneously, a leakage malfunction of the injector for the affected cylinder probably has occurred.

  • If DTC P0200 (Open or short in EDU or injector circuit) is present simultaneously, there probably is a fault in the circuit between the ECM and the injector. This fault may also be as a result of 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 is set simultaneously)

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

  • Connector connection (P0200 is 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 the intelligent tester.

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

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

Note

After replacing an injector, the ECM needs registration Click here.

Tech Tips

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

PROCEDURE


  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P1238)


    1. Connect the intelligent tester to the DLC3.

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

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

    4. Read DTCs.

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

      Tech Tips

      If any other codes besides P1238 are output, perform troubleshooting for those DTCs first.


    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 the intelligent tester to the DLC3.

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

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

    4. Read the value.

      Standard value
      Compensatory Injection Volume is between -4.9 mm3 and 4.9 mm3

      Tech Tips


      • If the injector is malfunctioning, the compensatory injection volume remains at -5.0 mm3or 5.0 mm3.

      • The compensatory injection volume is usually between -3.0 mm3and 3.0 mm3.

    5. Cylinders that have a compensation value which is more than the value specified above are considered to be faulty. Use the following steps to inspect and repair the cylinder.

      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 MALFUNCTIONING CYLINDER)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine and turn the tester ON.

    3. Select the following menu items: Powertrain / Engine and ECT / 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 pressure
      2,000 kPa (20.4 kgf/cm2, 290 psi)
      Minimum pressure
      1,630 kPa (16.6 kgf/cm2, 236 psi)
      Difference between each cylinder
      500 kPa (5.1 kgf/cm2, 73 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

    OK

  7. CHECK WHETHER DTC OUTPUT RECURS (DTC P1238)

    Tech Tips

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

    OK
    No DTC output

    OK

    CHECK FOR INTERMITTENT PROBLEMS

    NG

  8. REPLACE INJECTOR ASSEMBLY

    Replace the injection assembly 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