P0302
The content of this article reflects the changes identified in TSB - 10-13-007.DTC P0302: Cylinder 2 Misfire Detected
CAUTION: If DTC P0302 has been set, TCL related DTC U1120 is also set. After P0302 has been diagnosed, don't forget to erase DTC U1120.
TECHNICAL DESCRIPTION
- If a misfire occurs while the engine is running, the engine speed changes for an instant.
- The ECM
DESCRIPTIONS OF MONITOR METHODS
Monitor angular acceleration of crankshaft and detect malfunction when negative variation of the angular acceleration is large.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Camshaft position sensor
- Mass airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Throttle position sensor
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- Engine speed is between 500 and 6,500 r/min.
- Engine coolant temperature is higher than -10 °C (14 °F).
- Barometric pressure is higher than 76 kPa (22.4 in.Hg).
- Volumetric efficiency is at between 30 and 60 percent.
- Adaptive learning is complete for the vane which generates a crankshaft position signal.
- While the engine is running, excluding gear shifting, deceleration, sudden acceleration/deceleration and A/C compressor switching.
- The throttle deviation is -0.06 V/10 ms to +0.06 V/10 ms.
Judgement Criteria (change in the angular acceleration of the crankshaft is used for misfire detection)
- Misfire has occurred more frequently than allowed during the last 200 revolutions [when the catalyst temperature is higher than 1,000 °C (1,832 °F)].
or
- Misfire has occurred in 14 or more of the last 1,000 revolutions (corresponding to 1.5 times the limit of emission standard).
or
- Misfire has occurred in 11 or more of the last 1,000 revolutions (corresponding to 1.5 times the limit of emission standard).
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 15. OBD-II Drive Cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are)
- Fuel aeration due to low fuel level.
- Ignition system related part(s) failed.
- Low compression pressure.
- ECM failed.
- PCM failed.
DIAGNOSIS
Check whether fuel may be aerated due to low fuel level.
^ Check whether users have experienced the lack of fuel or not.
Q: Has the user ever experienced the lack of fuel?
YES: Ensure fuel level is not low, erase the DTC, and re-evaluate for misfire condition using the appropiate OBD-II Drive Cycle Procedure.
NO: Go to Step 1.
STEP 1. Check the No. 2 cylinder ignition coil spark.
1. Remove the No. 2 cylinder ignition coil.
2. Remove the No. 2 cylinder spark plug and connect to the No. 2 cylinder ignition coil.
3. Ground the spark plug side electrode securely.
- When the engine is cranked, the spark plug should spark.
Q: Did it spark?
YES: Go to Step 3.
NO: Go to Step 2.
STEP 2. Check the No. 2 cylinder spark plug.
Refer to Ignition System - On-vehicle Service - Spark Plug Check And Cleaning.
Q: Is the spark plug normal?
YES: Refer to INSPECTION PROCEDURE 32 - Ignition Circuit System. Inspection Procedure 32
NO: Replace the No. 2 cylinder spark plug. Then go to Step 5.
STEP 3. Check the compression.
Refer to On-Vehicle Service - Compression Pressure Check.
Q: Are there any abnormalities?
YES: Repair or replace it. Then go to Step 5.
NO: Go to Step 4.
STEP 4. Check the trouble symptoms.
1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 15. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0302 set?
YES: Replace the ECM or the PCM. When the ECM or the PCM is replaced, register the encrypted code. Refer to Encrypted Code Registration Criteria Table. Then go to Step 5.
NO: It can be assumed that this malfunction is intermittent.
STEP 5. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 15. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0302 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.