Inspection Procedure

HINT:

• If DTCs besides misfire DTCs are memorized simultaneously, troubleshoot the non-misfire DTCs first.
• Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
• If the misfire does not occur when the vehicle is brought to the workshop, the misfire can be confirmed by reproducing the condition of the freeze frame data. Also, after finishing the repair, confirm that there is no misfire (see CONFIRMATION DRIVING PATTERN ).
• On 6 and 8 cylinder engines, cylinder specific misfire fault codes are disabled at high engine speeds. If the misfire starts in a high engine speed area or the misfire occurs only in a high engine speed area, only the general fault code P0300 will be stored.

  When only a general misfire fault code like P0300 is stored:

  1. Erase the general misfire fault code from the ECM using the hand-held tester or OBD II scan tool.
  2. Start the engine and drive the confirmation pattern.
  3. Read the value of the misfire ratio for each cylinder. Or read the DTC.
  4. Perform repairs on the cylinder that has a high misfire ratio. Or repair the cylinder indicated by the DTC.
• When one of SHORT FT #1, LONG FT #1, SHORT FT #2 and LONG FT #2 in the freeze frame data is outside the range of Ω20 %, there is a possibility that the air-fuel ratio is becoming RICH (-20 % or less) or LEAN (+20 % or more).
• When COOLANT TEMP in the freeze frame data is less than 80°C (176°F), there is a possibility of misfire only during engine warm-up.
• If the misfire cannot be reproduced, the following reasons may apply: 1) the vehicle has low fuel, 2) improper fuel is being used, and 3) the ignition plug is contaminated.
• Be sure to check the value on the misfire counter after the repair.

1. CHECK OTHER DTC OUTPUT (IN ADDITION TO MISFIRE DTCS) 
   1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
   2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
   3. Select the item: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
   4. Read DTCs.

   Result: 

   DTC OUTPUT
   
   

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

   HINT:

   If any other codes besides P0300, P0301, P0302, P0303, P0304, P0305 or P0306 are output, perform troubleshooting for those DTCs first.

   B: GO TO RELEVANT  DIAGNOSTIC TROUBLE CODE CHART  

   A: GO TO NEXT STEP 

2. CHECK WIRE HARNESS, CONNECTOR AND VACUUM HOSE IN ENGINE ROOM 
   1. Check the connection conditions of the wire harness and connector.
   2. Check the piping of the vacuum hose.
   3. Check the vacuum hose for disconnection or breakage.

   NG: REPAIR OR REPLACE, THEN CONFIRM THAT THERE IS NO MISFIRE 

   OK: GO TO NEXT STEP 

3. CHECK CONNECTION OF PCV HOSE 

   NG: REPAIR OR REPLACE PCV HOSE 

   OK: GO TO NEXT STEP 

4. READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (NUMBER OF MISFIRE) 
   1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
   2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
   3. Start the engine.
   4. Select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / CYL#1 to CYL#6.
   5. Read the number of misfire on the hand-held tester or the OBD II scan tool.

   HINT:

   When a misfire is not reproduced, be sure to branch below based on the stored DTC.

   HAND HELD TESTER, READ VALUE RESULT
   
   

   High Misfire Rate Cylinder	Proceed to
   1 or 2 cylinders	A
   More than 3 cylinders	B

   B: Go to step   15 

   A: GO TO NEXT STEP 

5. CHECK SPARK PLUG AND SPARK OF MISFIRING CYLINDER 
   1. Remove the ignition coil assembly.
   2. Remove the spark plug.
   3. Check the spark plug type.

      Recommended spark plug: 

      RECOMMENDED SPARK PLUG
      
      

      DENSO made	SK20R11
      NGK made	IFR6A11

   4. Check the spark plug electrode gap.
      1. Electrode gap: 1.0 to 1.1 mm (0.039 to 0.043 in.) 
      1. Maximum electrode gap: 1.3 mm (0.051 in.) 
      NOTE: If adjusting the gap of a new spark plug, bend only "the base / ground" electrode. Do not touch the tip. Never attempt to adjust the gap on a used plug.
   5. Check the electrode for carbon deposits.
   6. Perform a spark test.
      CAUTION: Absolutely disconnect the each injector connectors.