ECD SYSTEM, Diagnostic DTC:P1238

DTC Code DTC Name
P1238 Injector Malfunction

DESCRIPTION

The ECM detects combustion deterioration for a specific cylinder.

Tech Tips


  • A cylinder which has an injection volume compensation value 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 assembly for the affected cylinder probably has occurred.

  • If DTC P0200 (Open or short in injector driver assembly or injector assembly 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 injector driver assembly.

  • If only DTC P1238 (Injector malfunction) is present, the probable cause is an injector assembly mechanical malfunction or insufficient compression (valve etc), not an open or short in the ECM, injector driver assembly and injector assembly circuit.

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

  • Injector assembly

  • Injector driver assembly (P0200 is set simultaneously)

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

  • Connector connection (P0200 is set simultaneously)

  • Compression pressure

  • Valve timing

  • ECM

Tech Tips

After confirming DTC P1238, check the internal fuel pressure by selecting the following menu items on the intelligent tester, "Powertrain / Engine and ECT / Data List / Fuel Press.

Reference:
Engine Speed Fuel Pressure (kPa)
Idling Approximately 25000 to 35000
2500 rpm (No engine load) Approximately 63000 to 71000

MONITOR DESCRIPTION

P1238 (Injection malfunction, except open or short in injector assembly 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 is also used to determine 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.

INSPECTION PROCEDURE

Note

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

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.

  • If DTCs other than P1238 are present simultaneously, first perform troubleshooting for those DTCs.

PROCEDURE


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


    1. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    2. Connect the intelligent tester to the DLC3.

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

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

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC P1238 is output A
      DTC P1238 and other DTCs are output B

      Tech Tips

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


    B

    GO TO DTC CHART Click here

    A

  2. CHECK HARNESS AND CONNECTOR (ENGINE WIRE HARNESS)

    Tech Tips

    Check the wire harness and connector connections.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    2. Connect the intelligent tester to the DLC3.

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

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Injection Feedback Val #1, #2, #3 and #4.

    5. Read its value displayed on the tester.

      Standard
      Result

      Compensatory Injection Volume (mm3/st)
      Standard -4.9 to 4.9

      Tech Tips


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

      • The compensatory injection volume is usually between -2.0 mm3/st and 2.0 mm3/st.

    6. 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 (INJECTOR CUT FOR IDENTIFYING MALFUNCTIONING CYLINDER)


    1. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    2. Connect the intelligent tester to the DLC3.

    3. Start the engine and turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Cylinder #1, #2, #3, and #4 Fuel Cut.

    5. Check the four cylinders in sequence to identify any faulty cylinders 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.

      • If the cylinder being tested is normal, there will be a significant change of idle speed when the fuel injection is stopped for that cylinder.


    NEXT

  5. CHECK CYLINDER COMPRESSION PRESSURE OF MALFUNCTIONING CYLINDER


    1. Check the cylinder compression pressure Click here.


    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

  6. CHECK IF DTC OUTPUT RECURS (DTC P1238)

    Tech Tips

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


    NG

    REPLACE INJECTOR ASSEMBLY Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

  7. REPLACE INJECTOR ASSEMBLY


    1. Replace the injector assembly Click here.


    NEXT

  8. CHECK IF DTC OUTPUT RECURS (DTC P1238)

    Tech Tips

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


    NEXT

    END