P0304
DTC P0304: Cylinder 4 Misfire DetectedMisfire Detected Circuit
- Refer to DTC P0201, P0203, P0205 - Injector Circuit.
- Refer to DTC P0202, P0204, P0206 - Injector Circuit.
CIRCUIT OPERATION
- Refer to DTC P0201, P0203, P0205 - Injector Circuit.
- Refer to DTC P0202, P0204, P0206 - Injector Circuit.
TECHNICAL DESCRIPTION
- If a misfire occurs while the engine is running, the engine speed changes for an instant.
- The ECM
DTC SET CONDITIONS
Check Conditions
- Engine speed is between 440 and 6,000 rpm.
- Engine coolant temperature is higher than -10 °C (14 °F).
- Intake air temperature is higher than -10 °C (14 °F).
- Barometric pressure is at between 76 kPa (11 psi) and 106 kPa (15 psi).
- 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 -0.059 v/10 ms to +0.059 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 950 °C (1,742 °F).
or
- Misfire has occurred in 20 or more of the last 1,000 revolutions (corresponding to 1.5 times the limit of emission standard).
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Ignition system related part (s) failed.
- Low compression pressure.
- Injector failed.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tool:
- MB991502: Scan Tool (MUT-II)
STEP 1. Check the spark plugs.
CAUTION
Do not attempt to adjust the gap of the platinum plug. Cleaning of the platinum plug may result in damage to the platinum tips. Therefore, if carbon deposits must be removed, use a plug cleaner and complete cleaning within 20 seconds to protect the electrode. Do not use a wire brush.
1. For the right bank cylinder, remove the intake manifold.
2. Check the plug gap and replace if the limit is exceeded.
Standard value: 1.0 - 1.1 mm (0.039 - 0.043 inch)
Limit: 1.3 mm (0.051 inch)
Q: Is the plug gap at the standard value?
YES: Go to Step 2.
NO: Replace the spark plug. Then go to Step 9.
STEP 2. Check the spark plug cable.
1. Check the cap and coating for cracks.
2. Measure the resistance.
Limit: maximum 22 kohms
Q: Is the measured resistance less than 22 kohms?
YES: Go to Step 3.
NO: Replace the spark plug cable. Then go to Step 9.
STEP 3. Check the injector.
1. Disconnect the injector connector B-01
2. Measure the resistance between injector side connector terminals No.1 and No.2.
Standard value: 13 - 16 ohms @ 20 °C (68 °F)
Q: Is the resistance between 13 and 16 ohms?
YES: Go to Step 4.
NO: Replace the injector. Then go to Step 9.
Connectors:
STEP 4. Check connector at injector and injector intermediate connector for damage.
a. Check the connector B-01 at injector and connector B-118 at injector intermediate connector when checking No.1 cylinder.
b. Check the connector B-O2 at injector when checking No.2 cylinder.
c. Check the connector B-05 at injector and connector B-118 at injector intermediate connector when checking No.3 cylinder.
d. Check the connector B-06 at injector when checking No.4 cylinder.
e. Check the connector B-26 at injector and connector B-118 at injector intermediate connector when checking No.5 cylinder
f. Check the connector B-25 at injector when checking No.6 cylinder.
Q: Is the connector in good condition?
YES: Go to Step 5.
NO: Repair or replace the injector. Refer to Harness Connector Inspection. Then go to Step 9.
Connectors:
STEP 5. Check connector C-111 at ECM
Q: Is the connector in good condition?
YES: Go to Step 6.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 9.
Connectors:
STEP 6. Check for harness damage between injector connector and ECM connector
a. Check the harness wire between injector connector B-01 (terminal No. 2) and ECM connector C-111 (terminal No.1)
b. Check the harness wire between injector connector B-02 (terminal No.2) and ECM connector C-111 (terminal No.9)
c. Check the harness. wire between injector connector B-05 (terminal No.2) and ECM connector C-111 (terminal No. 24)
d. Check the harness wire between injector connector B-06 (terminal No.2) and ECM connector C-111 (terminal No.2)
e. Check the harness wire between injector connector B-26 (terminal No.2) and ECM connector C-111 (terminal No. 10)
f. Check the harness wire between injector connector B-25 (terminal No.2) and ECM connector C-111 (terminal No. 25)
Q: Is the harness wire in good condition?
YES: Go to Step 7.
NO: Repair it. Then go to Step 9.
STEP 7. Check the compression.
Refer to On-vehicle Service - Compression Pressure Check.
Q: Are there any abnormalities?
YES: Go to Step 8.
NO: Repair or replace it. Then go to Step 9.
STEP 8. Replace the injector.
1. Replace the injector.
2. Carry out a test drive with the drive cycle pattern. Refer to Trouble Code Diagnosis OBD-II Drive Cycle - Procedure 6 Other Monitor.
3. Check the diagnostic trouble code (DTC).
Q: Are DTC P0301, P0302, P0303, P0304, P0305 and P0306 sets?
YES: Replace the ECM or PCM. Then go to Step 9.
NO: The inspection is complete.
STEP 9. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Trouble Code Diagnosis - OBD-II Drive Cycle - Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Are DTC P0301, P0302, P0303, P0304, P0305 and P0306 sets?
YES: Retry the troubleshooting.
NO: The inspection is complete.