Misfiring of cylinder 4 : Damages TWC (P0304)

Misfiring of cylinder 4 : Damages TWC (P0304)

The fault code P0304 refers to a misfire in cylinder 4, which can cause damage to the TWC (Three Way Catalyst) if left unaddressed. The TWC is a component of the vehicle's exhaust system that helps to reduce harmful emissions by converting exhaust gases into less harmful compounds. When an engine misfires, it can cause unburned fuel to enter the exhaust system, which can damage the TWC over time.

To address this issue, you should take your vehicle to a certified mechanic or dealership for diagnosis and repair. The mechanic will likely perform a diagnostic check to determine the cause of the misfire in cylinder 4. Some possible causes of a misfire include a faulty spark plug, a malfunctioning fuel injector, a vacuum leak, or an issue with the ignition system.

Once the root cause of the misfire has been identified, the mechanic can recommend the appropriate repair or replacement. This may involve replacing the faulty spark plug, repairing or replacing the fuel injector, fixing the vacuum leak, or addressing issues with the ignition system.

It is important to have this issue addressed promptly to prevent further damage to the TWC and ensure that your vehicle is running at peak performance. Continuing to drive with a misfire can cause damage to other components of the vehicle, increase emissions, and reduce fuel efficiency.

The repair process for a misfiring cylinder 4 and preventing damage to the TWC (Three Way Catalyst) typically involves the following steps:

1. Diagnosis: The mechanic will need to perform a diagnostic check to identify the cause of the misfire. This may involve using specialized diagnostic equipment to read fault codes, check the ignition system, fuel system, and other related components.

2. Inspect and Replace Spark Plugs: One of the most common causes of misfiring is a faulty spark plug. The mechanic will inspect the spark plug in cylinder 4 and replace it if necessary.

3. Inspect and Replace Fuel Injector: Another possible cause of misfiring is a faulty fuel injector. The mechanic will inspect the fuel injector in cylinder 4 and replace it if necessary.

4. Check Ignition System: The ignition system plays a crucial role in ensuring proper engine operation. The mechanic will check the ignition system for any issues and replace any damaged components.

5. Inspect and Repair Vacuum Leaks: Vacuum leaks can cause misfiring and damage to the TWC. The mechanic will inspect the vacuum system for any leaks and repair or replace any damaged components.

6. Monitor O2 Sensor Readings: The O2 sensor measures the amount of oxygen in the exhaust gas and plays an important role in the operation of the TWC. The mechanic will monitor the O2 sensor readings to ensure that the TWC is functioning properly.

7. Replace TWC: If the TWC has been damaged, the mechanic may recommend replacing it to ensure proper emissions control.

It is important to have this issue addressed promptly to prevent further damage to the TWC and ensure that your vehicle is running at peak performance. Continuing to drive with a misfire can cause damage to other components of the vehicle, increase emissions, and reduce fuel efficiency. Therefore, it is recommended to take your vehicle to a certified mechanic or dealership for diagnosis and repair.

Misfiring of cylinder 4 : Damages TWC (P0304)

Misfiring of cylinder 4 : Damages TWC (P0304)
Misfiring of cylinder 4 : Damages TWC (P0304)
Possible cause:
­ Combustion misfirings
Affected functions:
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Engine diagnosis
Engine running
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Test 1: Check component T1/4 (ignition coil cylinder 4).
Test 2: Check component Y62y4 (Fuel injector cylinder 4).
Test 3: Combustion misfirings
1. Check component T1/4 (ignition coil cylinder 4).
Warning!Hazard as a result of high voltage at the ignition system!
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Page 618
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Electronic ignition systems operate within a hazardous power range both at the low voltage side (primary circuit) as well as on the
high voltage side (secondary circuit).
­ Contacts with such parts can result in burns, heart flutter or cardiac arrest.
Rules of conduct and protective measures
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Persons with heart pacemakers must not perform any work on the ignition system.
Switch off the ignition when performing work on the ignition system.
Do not touch any parts of the ignition system when starting the engine or when the engine is running.
Wear protective shoes with rubber soles.
Do not install any uninsulated adapters into the ignition cables.
1. No further information available.
2. Check component Y62y4 (Fuel injector cylinder 4).
Safety note
Warning!Risk of explosion, poisoning and injury!Fuels are highly inflammable and toxic if inhaled. Fuels may cause skin damage. fuel
vapors are explosive, invisible and spread out at floor level, they are toxic if inhaled and produce giddiness and an anaesthetizing
effect.Rules of conduct and protective measures
­ Wear suitable protective clothing.
­ Pay attention to national safety precautions and regulations.
­ No fire, sparks, naked flames and smoking.
­ Ensure the work place is adequately ventilated.
­ Never drain or pour in fuels over assembly pits.
­ Store drained fuel in a suitable and sealed vessel.
­ Immediately eliminate any fuel which has flowed out.
First­aid measures
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Clean moistened skin with water and soap.
Change moistened clothing as quickly as possible.
If fuel gets into your eyes, rinse out your eyes immediately with water and contact a doctor if necessary.
Test 2.1: Test actuation of component Y62y4 (Fuel injector cylinder 4).
Test 2.2: Test signal voltage of component Y62y4 (Fuel injector cylinder 4).
Test 2.3: Check internal resistance of component Y62y4 (Fuel injector cylinder 4).
Test 2.4: Inspect component Y62y4 (Fuel injector cylinder 4) for leaks.
Test 2.5: Inspect operation and spray pattern of component Y62y4 (Fuel injector cylinder 4).
2.1. Test actuation of component Y62y4 (Fuel injector cylinder 4).
Test prerequisite
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Coolant temperature > 80? C
Engine RUNNING
Warning!Communication with ECU required.
2.2. Test signal voltage of component Y62y4 (Fuel injector cylinder 4).
Figure legend
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A ­ConnectionTest cable 35­pin socket box
001 ­Sockets of component N3/10 (ME­SFI [ME] control unit)
05 ­35­pin socket box
050 ­126­pin socket box
108 ­Test cable 266 589 01 63 00
N3/10 (ME­SFI [ME] control unit)2010 Mercedes Benz E 63 AMG Sedan (212.077) V8­6.3L (156.985)
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­ II 1­63ConnectionTest cable
­ III 64­126ConnectionTest cable
Warning!
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Connection A of test cable 108 may NOT be connected to connection B of the 126­pin socket box (050).
Test sequence
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Note
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Switch off ignition.
ConnectionMeasuring system
Observe oscilloscope pattern between sockets [M.47] 47 and [F.3] 99 of the 126­pole socket box tester.
Run engine.
Measuring system:Communication with ECU required
2.3. Check internal resistance of component Y62y4 (Fuel injector cylinder 4).
Figure legend
­ A ­ConnectionTest cable 35­pin socket box
­ 001 ­Sockets of component N3/10 (ME­SFI [ME] control unit)
­ 05 ­35­pin socket box
­ 050 ­126­pin socket box
­ 108 ­Test cable 266 589 01 63 00
­ N3/10 (ME­SFI [ME] control unit)
­ II 1­63ConnectionTest cable
­ III 64­126ConnectionTest cable
Warning!
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­
Connection A of test cable 108 may NOT be connected to connection B of the 126­pin socket box (050).
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Test sequence
­ Switch off ignition.
­ Connect socket box (126­pin) to component N3/10 (ME­SFI [ME] control unit).
­ Measure resistance with multimeter between sockets [M.47] 47 and [F.3] 99 of the 126­pole socket box tester.
Specified value
­ Resistor[11...17]ohms
Question
­
Is the measurement value OK?
YES
The measurement value is OK.Note
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In the event of stored faults with a high fault frequency count or in the event of customer complaints, check lines and connectors
for loose contact and corrosion..
NO
The measurement value is not OK.Test sequence
­ Switch off ignition.
­ Connect shop­made test cable set to component Y62y4 (Fuel injector cylinder 4).
­ Measure resistance with multimeter between pins (Y62) 1 and (Y62) 2
Specified value
­ Resistor[11...13]ohms
Question
­
Is the measurement value OK?
YES
The measurement value is OK.Possible cause and remedy
­
Lines to component Y62y4 (Fuel injector cylinder 4)2010 Mercedes Benz E 63 AMG Sedan (212.077) V8­6.3L (156.985)
Copyright ? 2013, ALLDATA
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NO
The measurement value is not OK.Possible cause and remedy
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Y62y4 (Fuel injector cylinder 4)
2.4. Inspect component Y62y4 (Fuel injector cylinder 4) for leaks.
Figure legend
­ A ­ConnectionTest cable 35­pin socket box
­ 001 ­Sockets of component N3/10 (ME­SFI [ME] control unit)
­ 05 ­35­pin socket box
­ 050 ­126­pin socket box
­ 108 ­Test cable 266 589 01 63 00
­ N3/10 (ME­SFI [ME] control unit)
­ II 1­63ConnectionTest cable
­ III 64­126ConnectionTest cable
Warning!
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­
Connection A of test cable 108 may NOT be connected to connection B of the 126­pin socket box (050).
Figure legend
­ 055Measuring beakerY62 (Fuel injectors)
Test sequence
­ Switch off ignition.
­ Remove fuel rail together with component Y62 (Fuel injectors).
­ Connect socket box (126­pin) to component N3/10 (ME­SFI [ME] control unit).
­ Bridge between sockets (F.4) 100 and (F.17) 113 of the 126­pole socket box tester.
­ Switch on ignition.
Specified value
­ Component Y62y4 (Fuel injector cylinder 4) must not drip.
Question
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Copyright ? 2013, ALLDATA
10.52SS
Was the test o.k.?
YES
The test was okay.Further possible causes of fault
­
Inspect operation and spray pattern of component Y62y4 (Fuel injector cylinder 4).
NO
The test was not okay.Possible cause and remedy
­
Y62y4 (Fuel injector cylinder 4)
2.5. Inspect operation and spray pattern of component Y62y4 (Fuel injector cylinder 4).
Figure legend
­ A ­ConnectionTest cable 35­pin socket box
­ 001 ­Sockets of component N3/10 (ME­SFI [ME] control unit)
­ 05 ­35­pin socket box
­ 050 ­126­pin socket box
­ 108 ­Test cable 266 589 01 63 00
­ N3/10 (ME­SFI [ME] control unit)
­ II 1­63ConnectionTest cable
­ III 64­126ConnectionTest cable
Warning!
­
­
Connection A of test cable 108 may NOT be connected to connection B of the 126­pin socket box (050).
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Figure legend(Shop­made tool)
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1xClutch 140 545 35 28
2xContact spring 004 545 56 26
1xRed banana connector
1xBlack banana connector
2,2 mRed cable with diameter 1,5 mm(Pin 1)
2,2 mBrown cable with diameter 1,5 mm(Pin 2)
2 mInsulation sheathing with diameter 6 mm
Test sequence
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Switch off ignition.
Remove fuel rail together with component Y62 (Fuel injectors).
Connect socket box (126­pin) to component N3/10 (ME­SFI [ME] control unit).
Insert bridge.
Bridge between sockets (F.2) 98 and (F.17) 113 of the 126­pole socket box tester.
Switch on ignition.
Component M3 (Fuel pump) runs.
Hold component Y62y4 (Fuel injector cylinder 4) in a vessel and briefly operate manually with shop­made test cable set at sockets2010 Mercedes Benz E 63 AMG Sedan (212.077) V8­6.3L (156.985)
Copyright ? 2013, ALLDATA
98 and 99 of the 126­pin socket box.
Specified value
­ Fuel injectors should eject fuel uniformly.
Question
­
Was the test o.k.?
YES
The test was okay. End of test
NO
The test was not okay.Possible cause and remedy
­ Y62y4 (Fuel injector cylinder 4)
End of test
3. Combustion misfirings
Warning!Communication with ECU required.