SFI SYSTEM, Diagnostic DTC:P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308

DTC Code DTC Name
P0300 Random / Multiple Cylinder Misfire Detected
P0301 Cylinder 1 Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0303 Cylinder 3 Misfire Detected
P0304 Cylinder 4 Misfire Detected
P0305 Cylinder 5 Misfire Detected
P0306 Cylinder 6 Misfire Detected
P0307 Cylinder 7 Misfire Detected
P0308 Cylinder 8 Misfire Detected

DESCRIPTION

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause increase in exhaust emission levels. High concentrations of HC can also cause increases in the Three-Way Catalytic Converter (TWC) temperature, which may cause damage to the TWC. To prevent this increase in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the TWC reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the Camshaft Position (CMP) sensor and the Crankshaft Position (CKP) sensor. The CMP sensor is used to identify any misfiring cylinders and the CKP sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed predetermined thresholds.

If the misfire exceeds the threshold levels, and could cause emission deterioration, the ECM illuminates the MIL and set a DTC.

DTC No. DTC Detection Condition Trouble Area
P0300

Simultaneous misfiring of several cylinders detected

(2 trip detection logic)


  • High temperature misfire occurs in the Three-way Catalytic Converter (TWC) (MIL blinks when detect immediately).

  • Catalyst deterioration misfire occurs (MIL illuminates).


  • Open or short in engine wire harness

  • Connector connection

  • Vacuum hose connections

  • Ignition system

  • Injector

  • Fuel pressure

  • Mass Air Flow (MAF) meter

  • Engine Coolant Temperature (ECT) sensor

  • Compression pressure

  • Valve clearance

  • Valve timing

  • Ventilation valve and hose

  • Ventilation hose connections

  • Air induction system

  • ECM

P0301

P0302

P0303

P0304

P0305

P0306

P0307

P0308

Misfiring of specific cylinder detected

(2 trip detection logic)


  • High temperature misfire occurs in the Three-way Catalytic Converter (TWC) (MIL blinks when detect immediately).

  • Catalyst deterioration misfire occurs (MIL illuminates).


  • Open or short in engine wire harness

  • Connector connection

  • Vacuum hose connections

  • Ignition system

  • Injector

  • Fuel pressure

  • Mass Air Flow (MAF) meter

  • Engine Coolant Temperature (ECT) sensor

  • Compression pressure

  • Valve clearance

  • Valve timing

  • Ventilation valve and hose

  • Ventilation hose connections

  • Air induction system

  • ECM

When DTCs for misfiring cylinders are randomly set, but DTC P0300 is not set, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only set when several misfiring cylinders are detected at the same time.

Reference: Inspection using an oscilloscope.

With the engine idling, check the waveform between terminals #10 to #80 and E1 of the ECM connectors.

Tech Tips

The correct waveform is as shown.

A01GLU0E10

MONITOR DESCRIPTION

A01GNJPE01

The ECM illuminates the MIL and sets a DTC when either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).


The ECM flashes the MIL (immediate detection logic) and sets a DTC (2 trip detection logic) when either one of the following conditions, which could cause the Three-Way Catalytic Converter (TWC) damage, is detected (2 trip detection logic).


WIRING DIAGRAM

Refer to DTC P0201 Click here for the wiring diagram of the fuel injectors.

Refer to DTC P0351 Click here for the wiring diagram of the ignition system.

CONFIRMATION DRIVING PATTERN


  1. Connect the GTS to the DLC3.

  2. Turn the engine switch on (IG).

  3. Turn the GTS on.

  4. Record the DTC(s) and freeze frame data.

  5. Using the GTS, switch the ECM from normal mode to check mode Click here.

  6. Read the misfire counts of each cylinder with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.

  7. Drive the vehicle several times with the conditions, such as engine rpm and engine load, shown in Misfire RPM and Misfire Load in the Data List.

    Tech Tips

    In order to store misfire DTCs, it is necessary to drive the vehicle for the period of time shown in the table below, with the Misfire RPM and Misfire Load in the Data List.

    Engine RPM Duration
    Idling 8 minutes or more
    1000 4.5 minutes or more
    2000 2.5 minutes or more
    3000 1.5 minute or more
  8. Check whether misfires have occurred by checking DTCs and freeze frame data.

    Tech Tips

    Do not turn the engine switch off until the stored DTC(s) and freeze data have been recorded. When the ECM returns to normal mode (default), the stored DTC(s), freeze frame data and other data will be erased.

  9. Record the DTC(s), freeze frame data and misfire counts.

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

INSPECTION PROCEDURE

Tech Tips


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

  • Read freeze frame data using the GTS. Freeze frame data records the engine conditions 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.

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

  • The misfire still cannot be reproduced even though the conditions stored in the freeze frame data have been duplicated, one of the following factors is considered to be a possible cause of the problem:


    1. The fuel tank is low full.

    2. Improper fuel is used.

    3. The spark plugs have been contaminated.

    4. The problem is complex.

  • After finishing repairs, check the misfire counts of the cylinders.

  • Be sure to confirm that no misfiring cylinder DTCs are set again by conducting the confirmation driving pattern, after repairs.

  • For 6 and 8 cylinder engines, the ECM intentionally does not set the specific misfiring cylinder DTCs at high engine RPM. If misfires occur only in high engine RPM areas, only DTC P0300 is set.

    In the event of DTC P0300 being present, perform the following operations:


    1. Clear the DTC Click here.

    2. Start the engine and conduct the confirmation driving pattern.

    3. Read the misfiring rates of each cylinder or DTC(s) using the GTS.

    4. Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.

    5. After finishing repairs, conduct the confirmation driving pattern again, in order to verify that DTC P0300 is not set.

  • When one of Short FT #1, Long FT #1, Short FT #2 or Long FT #2 in the freeze frame data is outside the range of +/-20%, the air-fuel ratio may be RICH (-20% or less) or LEAN (+20% or more).

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

PROCEDURE


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


    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 DTCs.

      Result
      Display (DTC Output) Proceed to
      P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 A
      P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 and other DTCs B

      Tech Tips

      If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308 are output, troubleshoot those DTCs first.


    B
    A
  2. CHECK PCV HOSE CONNECTIONS


    1. Check the PCV hose connections.

      OK
      PCV hose is connected correctly and is not damaged.

    NG
    OK
  3. READ VALUE USING GTS (MISFIRE RPM AND MISFIRE LOAD)


    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 / Misfire RPM and Misfire Load.

    5. Read and note the Misfire RPM and Misfire Load values.

      Tech Tips

      The Misfire RPM and Misfire Load values indicate the vehicle conditions under which the misfire occurred.


    NEXT
  4. READ VALUE USING GTS (MISFIRE COUNT)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Clear DTCs Click here.

    5. Enter the following menus: Powertrain / Engine / Data List / Cylinder #1 to #8 Misfire Count.

    6. Allow the engine to idle.

    7. Read each value of Cylinder #1 to #8 Misfire Count displayed on the GTS. If no misfire counts occur in any cylinders, perform the following procedures:


      1. Start the engine and let it idle.

      2. Move the shift lever to D.

      3. Check the Cylinder #1 to #8 Misfire Count.

      4. If misfire counts are still not displayed, perform procedure "A" and "B", and then check the misfire counts again.

        Procedure A: Drive the vehicle while satisfying the Misfire RPM and Misfire Load values noted in the "Read Value Using GTS (Misfire RPM and Misfire Load)" procedure above.

        Procedure B: Read the Cylinder #1 to #8 Misfire Count or the DTCs output on the GTS.

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

    B
    A
  5. INSPECT SPARK PLUG


    1. Inspect the spark plug of the misfiring cylinder Click here.


    NG
    OK
  6. CHECK FOR SPARKS AND IGNITION


    1. Perform a spark test Click here.

      CAUTION:

      Always disconnect all the injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.

      OK
      Spark jumps across electrode gap.

    NG
    OK
  7. CHECK CYLINDER COMPRESSION PRESSURE


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


    NG
    OK
  8. CHECK FUEL INJECTOR (POWER SOURCE VOLTAGE)


    1. A01GMHGE02

      Disconnect the fuel injector connector.

    2. Turn the engine switch on (IG).

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      J5-2 - Body ground Engine switch on (IG) 11 to 14 V
      I5-2 - Body ground Engine switch on (IG) 11 to 14 V
      J6-2 - Body ground Engine switch on (IG) 11 to 14 V
      I6-2 - Body ground Engine switch on (IG) 11 to 14 V
      J7-2 - Body ground Engine switch on (IG) 11 to 14 V
      I7-2 - Body ground Engine switch on (IG) 11 to 14 V
      J8-2 - Body ground Engine switch on (IG) 11 to 14 V
      I8-2 - Body ground Engine switch on (IG) 11 to 14 V

    NG
    OK
  9. CHECK HARNESS AND CONNECTOR (ECM - FUEL INJECTOR)


    1. A01GJ3EE02

      Disconnect the E2 and E4 ECM connectors.

    2. Disconnect the fuel injector connector.

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

      Standard resistance (Check for open)
      Tester Connection Condition Specified Condition
      J5-1 - E4-17 (#10) Always Below 1 Ω
      I5-1 - E2-11 (#20) Always Below 1 Ω
      J6-1 - E4-16 (#30) Always Below 1 Ω
      I6-1 - E2-10 (#40) Always Below 1 Ω
      J7-1 - E4-15 (#50) Always Below 1 Ω
      I7-1 - E2-9 (#60) Always Below 1 Ω
      J8-1 - E4-14 (#70) Always Below 1 Ω
      I8-1 - E2-8 (#80) Always Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Condition Specified Condition
      J5-1 or E4-17 (#10) - Body ground Always 10 kΩ or higher
      I5-1 or E2-11 (#20) - Body ground Always 10 kΩ or higher
      J6-1 or E4-16 (#30) - Body ground Always 10 kΩ or higher
      I6-1 or E2-10 (#40) - Body ground Always 10 kΩ or higher
      J7-1 or E4-15 (#50) - Body ground Always 10 kΩ or higher
      I7-1 or E2-9 (#60) - Body ground Always 10 kΩ or higher
      J8-1 or E4-14 (#70) - Body ground Always 10 kΩ or higher
      I8-1 or E2-8 (#80) - Body ground Always 10 kΩ or higher

    NG
    OK
  10. CHECK FUEL INJECTOR OF MISFIRING CYLINDER


    1. Check the fuel injector injection [whether fuel volume is high or low, and whether injection pattern is poor] Click here.


    NG
    OK
  11. CHECK AIR INDUCTION SYSTEM


    1. Check the air induction system for vacuum leakage.

      OK
      No leakage in air induction system.

    NG
    OK
  12. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG
    OK
  13. READ VALUE USING GTS (COOLANT TEMP)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG) and turn the GTS on.

    3. Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.

    4. Read the Coolant Temp value when the engine is cold and warmed-up.

      Standard
      ECT when the engine is cold: Same as ambient temperature
      ECT when the engine is warmed up: 75 to 95°C (167 to 203°F)

    NG
    OK
  14. READ VALUE USING GTS (MAF Sensor 1, MAF Sensor 2)


    1. Connect the GTS to the DLC3.

    2. Start the engine and turn the GTS on.

    3. Enter the following menus: Powertrain / Engine / Data List / Engine Speed, Coolant Temp, MAF Sensor 1 and MAF Sensor 2.

    4. Allow the engine to idle until the ECT reaches 75°C (167°F) or higher.

    5. Read MAF Sensor 1 and MAF Sensor 2 with the engine speed at 3000 rpm.

      Standard
      Between 3.6 to 17.6 g/s (shift lever is in N position and A/C is OFF)

    NG
    OK
  15. CHECK VALVE TIMING

    A01GM73E01

    1. Remove the cylinder head cover bank 1 and bank 2.

    2. Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.

    3. Rotate the crankshaft pulley and align its notch to timing mark 0 of the timing chain cover. Check that the timing marks of the camshaft timing gears and camshaft timing exhaust gears are at the positions shown in the illustration.

      OK
      Timing marks on camshaft timing gears are aligned as shown in the illustration.
    4. Reinstall the cylinder head cover.


    OK
    NG
  16. CHECK AIR INDUCTION SYSTEM


    1. Check the air induction system for vacuum leakage.

      OK
      No leakage in air induction system.

    NG
    OK
  17. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG
    OK
  18. READ VALUE USING GTS (COOLANT TEMP)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG) and turn the GTS on.

    3. Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.

    4. Read the Coolant Temp value when the engine is cold and warmed-up.

      Standard
      ECT when the engine is cold: Same as ambient temperature
      ECT when the engine is warmed up: 75 to 95°C (167 to 203°F)

    NG
    OK
  19. READ VALUE USING GTS (MAF Sensor 1, MAF Sensor 2)


    1. Connect the GTS to the DLC3.

    2. Start the engine and turn the GTS on.

    3. Enter the following menus: Powertrain / Engine / Data List / Engine Speed, Coolant Temp, MAF Sensor 1 and MAF Sensor 2.

    4. Allow the engine to idle until the ECT reaches 75°C (167°F) or higher.

    5. Read MAF Sensor 1 and MAF Sensor 2 with the engine speed at 3000 rpm.

      Standard
      Between 3.6 to 17.6 g/s (shift lever is in N position and A/C is OFF)

    NG
    OK
  20. CHECK VALVE TIMING

    A01GM73E01

    1. Remove the cylinder head cover bank 1 and bank 2.

    2. Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.

    3. Rotate the crankshaft pulley and align its notch to timing mark 0 of the timing chain cover. Check that the timing marks of the camshaft timing gears and camshaft timing exhaust gears are at the positions shown in the illustration.

      OK
      Timing marks on camshaft timing gears are aligned as shown in the illustration.
    4. Reinstall the cylinder head cover.


    NG
    OK
  21. INSPECT SPARK PLUG


    1. Inspect the spark plug of the misfiring cylinder Click here.


    NG
    OK
  22. CHECK FOR SPARKS AND IGNITION


    1. Perform a spark test Click here.

      CAUTION:

      Always disconnect all injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.

      OK
      Sparks jump across electrode gap.

    NG
    OK
  23. CHECK CYLINDER COMPRESSION PRESSURE


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


    NG
    OK
  24. CHECK FUEL INJECTOR (POWER SOURCE VOLTAGE)


    1. A01GMHGE02

      Disconnect the fuel injector connector.

    2. Turn the engine switch on (IG).

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      J5-2 - Body ground Engine switch on (IG) 11 to 14 V
      I5-2 - Body ground Engine switch on (IG) 11 to 14 V
      J6-2 - Body ground Engine switch on (IG) 11 to 14 V
      I6-2 - Body ground Engine switch on (IG) 11 to 14 V
      J7-2 - Body ground Engine switch on (IG) 11 to 14 V
      I7-2 - Body ground Engine switch on (IG) 11 to 14 V
      J8-2 - Body ground Engine switch on (IG) 11 to 14 V
      I8-2 - Body ground Engine switch on (IG) 11 to 14 V

    NG
    OK
  25. CHECK HARNESS AND CONNECTOR (ECM - FUEL INJECTOR)


    1. A01GJ3EE02

      Disconnect the E2 and E4 ECM connectors.

    2. Disconnect the fuel injector connector.

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

      Standard resistance (Check for open)
      Tester Connection Condition Specified Condition
      J5-1 - E4-17 (#10) Always Below 1 Ω
      I5-1 - E2-11 (#20) Always Below 1 Ω
      J6-1 - E4-16 (#30) Always Below 1 Ω
      I6-1 - E2-10 (#40) Always Below 1 Ω
      J7-1 - E4-15 (#50) Always Below 1 Ω
      I7-1 - E2-9 (#60) Always Below 1 Ω
      J8-1 - E4-14 (#70) Always Below 1 Ω
      I8-1 - E2-8 (#80) Always Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Condition Specified Condition
      J5-1 or E4-17 (#10) - Body ground Always 10 kΩ or higher
      I5-1 or E2-11 (#20) - Body ground Always 10 kΩ or higher
      J6-1 or E4-16 (#30) - Body ground Always 10 kΩ or higher
      I6-1 or E2-10 (#40) - Body ground Always 10 kΩ or higher
      J7-1 or E4-15 (#50) - Body ground Always 10 kΩ or higher
      I7-1 or E2-9 (#60) - Body ground Always 10 kΩ or higher
      J8-1 or E4-14 (#70) - Body ground Always 10 kΩ or higher
      I8-1 or E2-8 (#80) - Body ground Always 10 kΩ or higher

    NG
    OK
  26. CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER


    1. Check the fuel injector injection [whether fuel volume is high or low, and whether injection pattern is poor] Click here.


    NG
    OK
  27. CHECK HARNESS AND CONNECTOR


    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.


    NEXT
  28. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Clear the DTCs Click here.

    5. Turn the engine switch off.

    6. Turn the engine switch on (IG) and turn the GTS on.

    7. Start the engine and warm it up.

    8. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

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

    10. Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308.

    11. Check the DTC judgment result.

      Result
      Display (DTC Output) Proceed to

      ABNORMAL

      (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308)

      A

      NORMAL

      (No DTC)

      B

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

    A01GLWCE03

    1. Disconnect the E13 and E22 MAF meter connectors.

    2. Disconnect the E1 ECM connector.

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

      Standard resistance (Check for open)
      Tester Connection Condition Specified Condition
      E13-1 (VG) - E1-25 (VG) Always Below 1 Ω
      E13-2 (E2G) - E1-24 (E2G) Always Below 1 Ω
      E22-1 (VGR) - E1-23 (VG2) Always Below 1 Ω
      E22-2 (EVGR) - E1-32 (E2G2) Always Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Condition Specified Condition
      E13-1 (VG) or E1-25 (VG) - Body ground Always 10 kΩ or higher
      E22-1 (VGR) or E1-23 (VG2) - Body ground Always 10 kΩ or higher

    NG
    OK
  30. REPLACE MASS AIR FLOW METER


    1. Replace the mass air flow meter Click here.

      Tech Tips

      If the results of the inspections performed in steps 14 and 19 indicated no problem, proceed to the next step without replacing the mass air flow meter.


    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 Click here.

    5. Turn the engine switch off.

    6. Turn the engine switch on (IG) and turn the GTS on.

    7. Start the engine and warm it up.

    8. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

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

    10. Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308.

    11. Check the DTC judgment result.

      Result
      Display (DTC Output) Proceed to

      NORMAL

      (No DTC)

      A

      ABNORMAL

      (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308)

      B

    B
    A
  32. CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER


    1. Change the installed spark plug to a spark plug that functions normally.

    2. Perform a spark test.

      CAUTION:

      Always disconnect all injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.


      1. Install the spark plug to the ignition coil and connect the ignition coil connector.

      2. Disconnect the injector connectors.

      3. Ground the spark plug.

      4. Check if sparks occur while the engine is being cranked.

        OK
        Sparks jump across electrode gap.

    NG
    OK
  33. CHANGE TO NORMAL IGNITION COIL ASSEMBLY AND CHECK SPARK OF MISFIRING CYLINDER


    1. Change the ignition coil to an ignition coil that functions normally.

    2. Perform a spark test.

      CAUTION:

      Always disconnect all fuel injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.


      1. Install the spark plug to the ignition coil and connect the ignition coil connector.

      2. Disconnect the fuel injector connectors.

      3. Ground the spark plug.

      4. Check if sparks occur while the engine is being cranked.

        OK
        Sparks jump across electrode gap.

    NG
    OK
  34. CHECK FUEL LINE


    1. Check the fuel lines for leaks or blockage.


    NG
    OK