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Home >> Mercedes Benz Truck >> 2012 >> R 350 4MATIC (251.157) V6-3.5L (276.958) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0304 >> P030484 >> Part 1

Part 1


Combustion misfiring of cylinder 4 has been detected. There is a signal below the permissible limit value.
Combustion misfires


Test 1: Continue

1.

Test 1.1: Continue

1.1.

Test 1.1.1: Continue

1.1.1.

Test 1.1.1.1: Continue

1.1.1.1.

Test 1.1.1.1.1: Continue

1.1.1.1.1.

Test 1.1.1.1.1.1: Continue

1.1.1.1.1.1.

Test 1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.
Please check if all of the following conditions are fulfilled:
Is the DTC[P030000: Combustion misfiring has been detected.] in any state?
Is the DTC[P030084: Combustion misfiring has been detected. There is a signal below the permissible limit value.] in any state?
Is the DTC[P030085: Combustion misfiring has been detected. There is a signal above the permissible limit value.] in any state?
Is the DTC[P030100: Combustion misfiring of cylinder 1 has been detected.] in any state?
Is the DTC[P030184: Combustion misfiring of cylinder 1 has been detected. There is a signal below the permissible limit value.] in any state?
Is the DTC[P030185: Combustion misfiring of cylinder 1 has been detected. There is a signal above the permissible limit value.] in any state?
Is the DTC[P030200: Combustion misfiring of cylinder 2 has been detected.] in any state?
Is the DTC[P030284: Combustion misfiring of cylinder 2 has been detected. There is a signal below the permissible limit value.] in any state?
Is the DTC[P030285: Combustion misfiring of cylinder 2 has been detected. There is a signal above the permissible limit value.] in any state?
Is the DTC[P030300: Combustion misfiring of cylinder 3 has been detected.] in any state?
Is the DTC[P030384: Combustion misfiring of cylinder 3 has been detected. There is a signal below the permissible limit value.] in any state?
Is the DTC[P030385: Combustion misfiring of cylinder 3 has been detected. There is a signal above the permissible limit value.] in any state?
Is the DTC[P030400: Combustion misfiring of cylinder 4 has been detected.] in any state?
Is the DTC[P030484: Combustion misfiring of cylinder 4 has been detected. There is a signal below the permissible limit value.] in any state?
Is the DTC[P030485: Combustion misfiring of cylinder 4 has been detected. There is a signal above the permissible limit value.] in any state?
Is the DTC[P030500: Combustion misfiring of cylinder 5 has been detected.] in any state?
Is the DTC[P030584: Combustion misfiring of cylinder 5 has been detected. There is a signal below the permissible limit value.] in any state?
Is the DTC[P030585: Combustion misfiring of cylinder 5 has been detected. There is a signal above the permissible limit value.] in any state?
Is the DTC[P030600: Combustion misfiring of cylinder 6 has been detected.] in any state?
Is the DTC[P030684: Combustion misfiring of cylinder 6 has been detected. There is a signal below the permissible limit value.] in any state?
Is the DTC[P030685: Combustion misfiring of cylinder 6 has been detected. There is a signal above the permissible limit value.] in any state?
Is the DTC[P030700: Combustion misfiring of cylinder 7 has been detected.] in any state?
Is the DTC[P030784: Combustion misfiring of cylinder 7 has been detected. There is a signal below the permissible limit value.] in any state?
Is the DTC[P030785: Combustion misfiring of cylinder 7 has been detected. There is a signal above the permissible limit value.] in any state?
Is the DTC[P030800: Combustion misfiring of cylinder 8 has been detected.] in any state?
Is the DTC[P030884: Combustion misfiring of cylinder 8 has been detected. There is a signal below the permissible limit value.] in any state?
Is the DTC[P030885: Combustion misfiring of cylinder 8 has been detected. There is a signal above the permissible limit value.] in any state?
Is the DTC[P036300: Combustion misfiring was detected during stratified operation.] in any state?
Communication with ECU required.


YES

Test 1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.
Check exhaust back pressure.


Test 1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.
Test prerequisites

- There is no fault code present which can affect the measurement value.
- Check oil level and correct if necessary.
- An oil change is not necessary.

Test procedure

- Remove oxygen sensor upstream of catalytic converter.
- Connect special tool '103 589 00 91 00' to component 'Catalytic converter' in the vehicle.
- Connect pressure gauge.
- In vehicles with automatic transmission, select transmission mode 'M' or 'C'.
- Drive the vehicle on the road or on the output dynamometer in gear 3 or selector lever position '3'.
- Perform measurement of exhaust back pressure during acceleration in full load mode using a pressure gauge.
- Erase fault memory.

Notes

- Coat thread of special tool with heat-resistant lubricant. ( Number of replacement part : 000 989 76 51 )
- For vehicles with all-wheel drive, drive vehicle on the road in gear 3.
- Check maximum permissible output of dynamometer!
- Inspect components of exhaust system using endoscope. The catalytic converter can be inspected via the threaded connection of the oxygen sensor.



Test 1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.

- The actual values are OK.

End of test


Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.
Check fuel high pressure circuit.


Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.
M276 cylinder specific?


YES

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.
Loss of fuel pressure ?


YES
Fuel overpressure ?


YES
Check fuel high pressure circuit.

- The fuel pressure is OK.

Note

- Check electrical connector on component 'Fuel system high pressure pump' for proper seating, good contact and correct engagement.

End of test


Check gasoline fuel for water and diesel content.


Safety information for fuel


Risk of explosion, poisoning and injury!

- Fuels are highly flammable and poisonous when ingested.
- Fuels can cause skin damage.
- Fuel vapors are explosive, invisible and spread out at floor level, They are poisonous when inhaled, producing giddiness and having an anesthetizing effect.

Safety instructions/precautions

- Wear suitable protective clothing.
- Observe country-specific safety regulations and rules.
- No fire, sparks, naked flames or smoking.
- Ensure that the workplace is sufficiently ventilated.
- Never drain or fill fuels above maintenance pits.
- Store drained fuel in suitable, lockable receptacles.
- Immediately remove escaped fuel.

First aid measures

- Clean fuel-soaked skin with water and soap.
- Change fuel-soaked clothing as soon as possible.
- If fuel comes into contact with eyes, immediately flush eyes with water and visit a doctor if necessary.



Legend

- (043) Pressure gauge
- (055) Measuring cup
- (069) Pressure hose (119 589 04 63 00)

Test procedure

- Switch off ignition.
- Connect pressure gauge.
- Hold open fuel line in measuring cup .
- Switch on ignition.
- Actuation of fuel pump
- Drain off about 0.5 l of fuel.

Actuation of fuel pump

Notes




Switch on fuel pump.




Switch off fuel pump.

Component 'M3 (Fuel pump)' is actuated for a duration of 60s when button 'Start' is pressed.







Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.
Check gasoline for water content.

- There is water in the fuel.

Possible cause and remedy

- Exchange the fuel. Flush tank system with approx. 5 l of fuel.

End of test



Test result
Procedure

- Erase fault memory and perform a test drive.

Note
Component 'N3/10 (ME-SFI [ME] control unit)' has no malfunction and must not be replaced.
End of test


End of test
Result: Fail


NO
Fuel pressure over limit


YES
Fuel pressure under limit


YES
Check fuel high pressure circuit.

- The fuel pressure is OK.

Note

- Check electrical connector on component 'Fuel system high pressure pump' for proper seating, good contact and correct engagement.

End of test


Check gasoline fuel for water and diesel content.


Safety information for fuel


Risk of explosion, poisoning and injury!

- Fuels are highly flammable and poisonous when ingested.
- Fuels can cause skin damage.
- Fuel vapors are explosive, invisible and spread out at floor level, They are poisonous when inhaled, producing giddiness and having an anesthetizing effect.

Safety instructions/precautions

- Wear suitable protective clothing.
- Observe country-specific safety regulations and rules.
- No fire, sparks, naked flames or smoking.
- Ensure that the workplace is sufficiently ventilated.
- Never drain or fill fuels above maintenance pits.
- Store drained fuel in suitable, lockable receptacles.
- Immediately remove escaped fuel.

First aid measures

- Clean fuel-soaked skin with water and soap.
- Change fuel-soaked clothing as soon as possible.
- If fuel comes into contact with eyes, immediately flush eyes with water and visit a doctor if necessary.



Legend

- (043) Pressure gauge
- (055) Measuring cup
- (069) Pressure hose (119 589 04 63 00)

Test procedure

- Switch off ignition.
- Connect pressure gauge.
- Hold open fuel line in measuring cup .
- Switch on ignition.
- Actuation of fuel pump
- Drain off about 0.5 l of fuel.

Actuation of fuel pump

Notes




Switch on fuel pump.




Switch off fuel pump.

Component 'M3 (Fuel pump)' is actuated for a duration of 60s when button 'Start' is pressed.







Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.
Check gasoline for water content.

- There is water in the fuel.

Possible cause and remedy

- Exchange the fuel. Flush tank system with approx. 5 l of fuel.

End of test



Test result
Procedure

- Erase fault memory and perform a test drive.

Note
Component 'N3/10 (ME-SFI [ME] control unit)' has no malfunction and must not be replaced.
End of test


End of test
Result: Fail


NO
Check component 'B4/25 (Fuel pressure and temperature sensor)' by means of actual value.


Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.
Check power supply of component 'B4/25 (Fuel pressure and temperature sensor)'.
Test procedure
Switch off ignition.
Disconnect 4-pin plug-in connector of component 'B4/25 (Fuel pressure and temperature sensor)'.
Switch on ignition.
[B4/25x1] Measure direct voltage with multimeter between 1 and 4 [B4/25x1]
Specified value
The measured value must be between 4.75V and 5.25V.
Question
Is the measured value OK?







End of test
No successor specified


NO
Check component 'B4/25 (Fuel pressure and temperature sensor)' by means of actual value.


Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.

Test 1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1: Continue

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.
Check power supply of component 'B4/25 (Fuel pressure and temperature sensor)'.
Test procedure
Switch off ignition.
Disconnect 4-pin plug-in connector of component 'B4/25 (Fuel pressure and temperature sensor)'.
Switch on ignition.
[B4/25x1] Measure direct voltage with multimeter between 1 and 4 [B4/25x1]
Specified value
The measured value must be between 4.75V and 5.25V.
Question
Is the measured value OK?







End of test
No successor specified


NO
Fuel pressure over limit


YES
Fuel pressure under limit


YES
Check fuel high pressure circuit.

- The fuel pressure is OK.

Note

- Check electrical connector on component 'Fuel system high pressure pump' for proper seating, good contact and correct engagement.

End of test
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