SFI SYSTEM, Diagnostic DTC:P1302

DTC Code DTC Name
P1302 Misfire Catalyst Damage Levels

DESCRIPTION

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P1302 Misfire Catalyst Damage Levels

DTC Detection Condition


    Enable Criteria

  • Battery voltage between 10 - 16 V

  • Coolant temperature between 10 - 120°C (14 - 248°F)

  • Engine speed between 630 - 8010 rpm

  • Altitude less than 8000 ft (2438 m) / Baro 75.6 kPa or higher

  • Fuel level 5 liters (1.3 US gallons) or higher

  • Engine load greater than 14 - 25% (Depending on engine speed)


    Malfunction Criteria

  • Catalyst Damage Failure - Misfire percentage higher than 9% - 25% (depending on engine speed and load), measured over 200 engine revolutions


    Diagnostic Mask

  • Fault code the MIL will be illuminated immediately and the ECM will take action to prevent catalyst damage


    Monitor

  • Continuous


    Potential failure modes

  • Injectors of related codes

  • VVT system (clearance or timing) or related codes

  • MAF meter

  • Connectors and wiring for signs of corrosion or loose connections

  • Spark plug / coil / cylinder compression

  • PCV system / hoses

  • Fuel pressure

  • Coolant temperature sensor

  • Vacuum hoses

  • ECU

  • Open or short in engine wire harness

  • Connector connection

  • Vacuum hose connections

  • Ignition system

  • Fuel injector assembly

  • Fuel pressure

  • Mass air flow meter

  • Engine coolant temperature sensor

  • Compression pressure

  • Valve timing

  • PCV valve and hose

  • PCV hose connections

  • Intake system

  • ECM

Comes on/Blinks*

*: The MIL flashes when a catalyst-damaging misfire is detected.

 DTC stored

MONITOR DESCRIPTION

When the engine misfire reaches a high enough percentage the engine emission output levels can exceed the allowed limits, and this will produce the fault code P1301.

If the misfire percentage is high enough and there is possibility that the catalyst may be damaged then code P1302 will be set. To prevent catalyst damage the ECM will take action to shut down the misfiring cylinder and the corresponding paired cylinder.

WIRING DIAGRAM

Refer to DTC P0102 for the mass air flow meter circuit.

Click here

Refer to P0261 for the Fuel Injector Circuit.

Click here

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following procedure.

Tech Tips


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

  • Read freeze frame data using the GTS. 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.

  • If the misfire does not recur when the vehicle is brought to the workshop, reproduce the conditions stored in the ECM as freeze frame data.

  • If the misfire still cannot be reproduced even though the conditions stored in the ECM as freeze frame data have been reproduced, the following factors can be considered to be a possible cause of the problem:


    1. There was insufficient fuel in the tank.

    2. Improper fuel was used.

    3. The spark plugs have been contaminated.

    4. The problem requires further diagnosis.

  • After finishing repairs, check the misfire counts of the cylinders (Cylinder #1 Misfire Count to Cylinder #4 Misfire Count).

  • When one of Short FT #1 or Long FT #1 in the freeze frame data is outside the range of +/-15%, the air fuel ratio may be rich (-15% or less) or lean (15% or higher).

  • When Coolant Temp in the freeze frame data is less than 75°C (167°F), the misfires have occurred only while warming up the engine.

  • An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be stored.

PROCEDURE


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


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Trouble Codes.

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC P1302 are output A
      DTC P1302 and other DTCs are output B

      Tech Tips

      If any DTCs other than P1302 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. CHECK PCV HOSE CONNECTIONS


    1. Check the PCV hose connections.

      Click here

      OK
      PCV valve and hose are correctly connected and are not damaged.
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE PCV HOSE

    OK

  3. CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 OR P0304)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Clear the DTCs.

    5. Turn the engine switch off and wait for at least 30 seconds.

    6. Turn the engine switch on (IG).

    7. Turn the GTS on.

    8. Start the engine.

    9. Warm up the engine.

    10. Using the GTS, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

    12. Input the DTC: P1302.

    13. Check the DTC judgment result.

      Result
      Result Proceed to

      NORMAL

      (DTCs are not output)

      		 A

      ABNORMAL

      (DTC P1302 is output)

      		 B

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

  4. READ VALUE USING GTS (CYLINDER MISFIRE COUNT)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Clear the DTCs.

    5. Start the engine and allow the engine to idle.

    6. Enter the following menus: Powertrain / Engine / Data List / Cylinder #1 Misfire Count, Cylinder #2 Misfire Count, Cylinder #3 Misfire Count and Cylinder #4 Misfire Count.

    7. Read each value for Cylinder #1 Misfire Count to Cylinder #4 Misfire Count displayed on the GTS. If no misfire counts occur in any cylinders, perform procedure [A] and [B] and then check the misfire counts again.

    8. Using the GTS, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored [A].

    9. Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the GTS [B].

      Result
      Result Proceed to
      Most misfires occur in only 1 or 2 cylinders A
      3 cylinders or more have equal misfire counts B

      Tech Tips


      • If the freeze frame data record of the engine coolant temperature is below 75°C (167°F), the misfire may be detected only when the engine is cold.

      • If the freeze frame data record of the Engine Run Time is below 120 seconds, the misfire may be detected immediately after the engine is started.


    B

    CHECK INTAKE SYSTEM Click here

    A

  5. INSPECT SPARK PLUG


    1. Inspect the spark plug of the misfiring cylinder.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the spark plug.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SPARK PLUG Click here

    OK

  6. CHECK FOR SPARK PLUG (SPARK TEST)


    1. Perform a spark test.

      Click here

      Tech Tips


      • If the result of the spark test is normal, proceed to the next step.

      • Perform "Inspection After Repair" after repairing or replacing the ignition system.

        Click here

      Result
      Proceed to
      NEXT

    NEXT

  7. CHECK CYLINDER COMPRESSION PRESSURE


    1. Measure the cylinder compression pressure of the misfiring cylinder.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the engine assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

  8. CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER


    1. Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor).

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel injector assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER Click here

    OK

  9. CHECK INTAKE SYSTEM


    1. Check the intake system for vacuum leaks.

      Click here

      OK
      No leaks from intake system.

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the intake system.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE INTAKE SYSTEM

    OK

  10. CHECK FUEL PRESSURE


    1. Check the fuel pressure.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    GO TO STEP 32 Click here

    OK

  11. READ VALUE USING ENGINE COOLANT TEMPERATURE SENSOR

    Result
    Proceed to
    OK
    NG

    1. Inspect the engine coolant temperature sensor.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the engine coolant temperature sensor.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  12. READ VALUE USING GTS (INTAKE AIR)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

    5. Read the value displayed on the GTS.

      OK
      Same as actual intake air temperature.
      Result
      Proceed to
      OK
      NG

      Tech Tips


      • If there is an open circuit, the GTS indicates -40°C (-40°F).

      • If there is a short circuit, the GTS indicates 140°C (284°F).


    NG

    REPLACE MASS AIR FLOW METER Click here

    OK

  13. READ VALUE USING GTS (MAF)

    Result
    Proceed to
    OK
    NG

    1. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Data List / Primary / MAF, Coolant Temp and Engine Speed.

    5. Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.

    6. Read MAF with the engine speed at 3000 rpm.

      Standard
      GTS Display Condition Specified Condition
      MAF

      Shift lever position: Neutral

      A/C: Off

      Engine Speed: 3000 rpm

      		 Between 5.0 gm/sec and 10.0 gm/sec
      Result
      Proceed to
      OK
      NG

    NG

    GO TO STEP 27 Click here

    OK

  14. CHECK ENGINE MECHANICAL SYSTEM


    1. Check for mechanical malfunctions that affect the valve timing, such as a jumped tooth or stretching of the timing chain.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA

    OK

  15. CHECK WHETHER DTC OUTPUT RECURS (DTC P1302)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Clear the DTCs.

    5. Turn the engine switch off and wait for at least 30 seconds.

    6. Turn the engine switch on (IG).

    7. Turn the GTS on.

    8. Start the engine.

    9. Warm up the engine.

    10. Using the GTS, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

    12. Input the DTC: P1302.

    13. Check the DTC judgment result.

      Result
      Result Proceed to

      NORMAL

      (DTCs are not output)

      		 A

      ABNORMAL

      (DTC P1302 is output)

      		 B

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    GO TO STEP 29 Click here

  16. CHECK INTAKE SYSTEM


    1. Check the intake system for vacuum leaks.

      Click here

      OK
      No leaks from intake system.

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the intake system.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE INTAKE SYSTEM

    OK

  17. CHECK FUEL PRESSURE


    1. Check the fuel pressure.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    INSPECT FUEL PUMP Click here

    OK

  18. INSPECT ENGINE COOLANT TEMPERATURE SENSOR

    Result
    Proceed to
    OK
    NG

    1. Inspect the engine coolant temperature sensor.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the engine coolant temperature sensor.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  19. READ VALUE USING GTS (INTAKE AIR)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

    5. Read the value displayed on the GTS.

      OK
      Same as actual intake air temperature.
      Result
      Proceed to
      OK
      NG

      Tech Tips


      • If there is an open circuit, the GTS indicates -40°C (-40°F).

      • If there is a short circuit, the GTS indicates 140°C (284°F).


    NG

    REPLACE MASS AIR FLOW METER Click here

    OK

  20. READ VALUE USING GTS (MAF)

    Result
    Proceed to
    OK
    NG

    1. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Data List / Primary / MAF, Coolant Temp and Engine Speed.

    5. Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.

    6. Read MAF with the engine speed at 3000 rpm.

      Standard
      GTS Display Condition Specified Condition
      MAF

      Shift lever position: Neutral

      A/C: Off

      Engine Speed: 3000 rpm

      		 Between 5.0 gm/sec and 10.0 gm/sec
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION) Click here

    OK

  21. INSPECT SPARK PLUG


    1. Inspect the spark plug of the misfiring cylinder.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the spark plug.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SPARK PLUG Click here

    OK

  22. CHECK FOR SPARK PLUG (SPARK TEST)


    1. Perform a spark test.

      Click here

      Tech Tips


      • If the result of the spark test is normal, proceed to the next step.

      • Perform "Inspection After Repair" after repairing or replacing the ignition system.

        Click here

      Result
      Proceed to
      NEXT

    NEXT

  23. CHECK CYLINDER COMPRESSION PRESSURE


    1. Measure the cylinder compression pressure of the misfiring cylinder.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the engine assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

  24. CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER


    1. Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor).

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel injector assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER Click here

    OK

  25. CHECK ENGINE MECHANICAL SYSTEM


    1. Check for mechanical malfunctions that affect the valve timing, such as a jumped tooth or stretching of the timing chain.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA

    OK

  26. CHECK WHETHER DTC OUTPUT RECURS (DTC P1302)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Clear the DTCs.

    5. Turn the engine switch off and wait for at least 30 seconds.

    6. Turn the engine switch on (IG).

    7. Turn the GTS on.

    8. Start the engine.

    9. Warm up the engine.

    10. Using the GTS, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

    12. Input the DTC: P1302.

    13. Check the DTC judgment result.

      Result
      Result Proceed to

      NORMAL

      (DTCs are not output)

      		 A

      ABNORMAL

      (DTC P1302 is output)

      		 B

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

  27. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)


    1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter and ECM.

      Click here

      Tech Tips

      Repair any problems.

      Result
      Proceed to
      NEXT

    NEXT

  28. CHECK WHETHER DTC OUTPUT RECURS (MISFIRE DTCS)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Clear the DTCs.

    5. Turn the engine switch off and wait for at least 30 seconds.

    6. Turn the engine switch on (IG).

    7. Turn the GTS on.

    8. Start the engine.

    9. Warm up the engine.

    10. Using the GTS, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

    12. Input the DTC: P1302.

    13. Check the DTC judgment result.

      Result
      Result Proceed to

      NORMAL

      (DTCs are not output)

      		 A

      ABNORMAL

      (DTC P1302 is output)

      		 B

    A

    END

    B

  29. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

    Result
    Proceed to
    OK
    NG

    1. Disconnect the A117 mass air flow meter connector.

    2. Disconnect the B142 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A117-3 (VG) - B142-43 (VG) Always Below 1 Ω
      A117-5 (E2G) - 142-21 (E2G) Always Below 1 Ω
      A117-3 (VG) or B142-43 (VG) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  30. REPLACE MASS AIR FLOW METER


    1. Replace the mass air flow meter.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the mass air flow meter.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  31. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Clear the DTCs.

    5. Turn the engine switch off and wait for at least 30 seconds.

    6. Turn the engine switch on (IG).

    7. Turn the GTS on.

    8. Start the engine.

    9. Warm up the engine.

    10. Using the GTS, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

    12. Input the DTC: P1302.

    13. Check the DTC judgment result.

      Result
      Result Proceed to

      NORMAL

      (DTCs are not output)

      		 A

      ABNORMAL

      (DTC P1302 is output)

      		 B

    A

    END

    B

    REPLACE ECM Click here

  32. INSPECT FUEL PUMP


    1. Inspect the fuel pump.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel pump.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE FUEL LINE

    NG

    REPLACE FUEL PUMP Click here