Toyota
Nissan Versa
 Sedan Service Manual
Engine » Engine control system (EC) » P0300, P0301, P0302, P0303, P0304 misfire
DTC Logic

DTC DETECTION LOGIC

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crankshaft position (CKP) sensor (POS) signal to vary, ECM can determine that a misfire is occurring.

Sensor Input signal to ECM ECM function
Crankshaft position sensor (POS) Engine speed On board diagnosis of misfire

The misfire detection logic consists of the following two conditions.

  1. One Trip Detection Logic (Three Way Catalyst Damage) On the 1st trip, when a misfire condition occurs that can damage the three way catalyst (TWC) due to overheating, the MIL will blink.

    When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions for a change.

    When the misfire condition decreases to a level that will not damage the TWC, the MIL will turn off.

    If another misfire condition occurs that can damage the TWC on a second trip, the MIL will blink.

    When the misfire condition decreases to a level that will not damage the TWC, the MIL will remain on.

    If another misfire condition occurs that can damage the TWC, the MIL will begin to blink again.

  2. Two Trip Detection Logic (Exhaust quality deterioration) For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MIL will only light when the misfire is detected on a second trip. During this condition, the ECM monitors the CKP sensor signal every 1,000 engine revolutions.

    A misfire malfunction can be detected on any one cylinder or on multiple cylinders.

DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0300 Multiple cylinder misfire detected Multiple cylinder misfire.
  • Improper spark plug
  • Insufficient compression
  • Incorrect fuel pressure
  • The fuel injector circuit is open or shorted
  • Fuel injector*
  • Intake air leak
  • The ignition signal circuit is open or shorted
  • Lack of fuel
  • Signal plate
  • A/F sensor 1
  • Incorrect PCV hose connection
P0301 No.1 cylinder misfire detected No. 1 cylinder misfires.
P0302 No. 2 cylinder misfire detected No. 2 cylinder misfires.
P0303 No. 3 cylinder misfire detected No. 3 cylinder misfires.
P0304 No. 4 cylinder misfire detected No. 4 cylinder misfires.

*: DTC is detected even where a malfunction occurs one side of the dual injector.

DTC CONFIRMATION PROCEDURE

1.PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.

  1. Turn ignition switch OFF and wait at least 10 seconds.
  2. Turn ignition switch ON.
  3. Turn ignition switch OFF and wait at least 10 seconds.

>> GO TO 2.

2.PERFORM DTC CONFIRMATION PROCEDUREI

  1. Start engine and warm it up to normal operating temperature.
  2. Turn ignition switch OFF and wait at least 10 seconds.
  3. Restart engine and let it idle for about 35 minutes.
  4. Check 1st trip DTC.

Is 1st trip DTC detected?

YES >> Go to EC, "Diagnosis Procedure".

NO >> GO TO 3.

3.PERFORM DTC CONFIRMATION PROCEDUREII

  1. Turn ignition switch OFF and wait at least 10 seconds.
  2. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for a certain time. Refer to the table below.

    Hold the accelerator pedal as steady as possible.

    The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following conditions should be satisfied at the same time.

    CAUTION: Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws when driving.

The time to driving varies according to the engine speed in the freeze frame data.

    3.   Check 1st trip DTC.

Is 1st trip DTC detected?

YES >> Go to EC, "Diagnosis Procedure".

NO >> INSPECTION END

    More about «P0300, P0301, P0302, P0303, P0304 misfire»:

    DTC Logic

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