Manufacturer Code Charts: 2043

Misfiring (P0300) ( See currently valid STIP )

Possible cause:

- Combustion misfirings
Affected functions:

- Engine diagnosis

-------------------------------------------------

Test 1: Test fuel pressure and delivery of component Fuel pump.

Test 2: Test gasoline fuel for water and diesel portions.

Test 3: Check smooth running of engine via fault counter.

Test 4: Check self-adaptation of mixture formation.

Test 5: Combustion misfirings

Test 6: AR01.00-P-1200L Compression pressure

1. Test fuel pressure and delivery of component Fuel pump.
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.
First-aid measures

- 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 1.1: Test fuel pressure and internal leaks of fuel system.

Test 1.2: Test delivery of component M3 (Fuel pump).

Test 1.3: Test current consumption of component M3 (Fuel pump).

1.1. Test fuel pressure and internal leaks of fuel system.
Test fuel pressure and internal leaks of fuel system.
Question

- Can the vehicle engine be operated at idle speed?

YES
Test fuel pressure and internal leaks of fuel system.
Figure legend

- 043Pressure gage(103 589 00 21 00)
- 055Measuring beaker
- 069Pressure hose(119 589 04 63 00)
Test sequence

- Switch off ignition.
- Connect test pressure gauge.
- Engine at idle
Specified value

- Pressure[3.7...4.1] bar
- Pressure[4.7...5.3] bar1)
Question

- Is the measurement value OK?
1)With control unit 'Fuel pump'

- TypeR230 A 230 540 29 45

YES
The measurement value is OK.Test prerequisite

- Test pressure gage is connected.
- Coolant temperature< 40°C
Test sequence

- Run the engine for a short time and switch off again.
- Switch off ignition.
Specified value

- Pressure after 40 minutes:[> 2.6] bar
Question

- Is the measurement value OK?

YES
The measurement value is OK.Further possible causes of fault

- Test delivery of component M3 (Fuel pump).

NO
The measurement value is not OK.Possible cause and remedy

- In the event of slow pressure drop:Check components 'Y62 (Fuel injectors)'.
- In the event of rapid pressure drop:Check valve in component Fuel filter

NO
Check component B4/7 (Fuel pressure sensor). ( Engine is starting. )
Figure legend/figure

- N118 -Control unitFuel pump
- 55/1 -Fuel filter with integrated pressure regulator
- M3 -Fuel pump
- B4/7 -Pressure sensorFuel
Test sequence

- Switch off ignition.
- Detach coupling at component B4/7 (Fuel pressure sensor).
- Start engine.
Specified valueFuel pressure

- Pressure> 8 bar
Question

- Is the measurement value OK?

YES
Check power supply of component B4/7 (Fuel pressure sensor).
The measurement value is OK.Figure legend/figure

- 55 -Fuel filter with integrated pressure regulator
- 55/2 -Pressure regulator
- B4/7 -Pressure sensorFuel
Test sequence

- Switch off ignition.
- Detach coupling at component B4/7 (Fuel pressure sensor).
- Measure direct voltage with multimeter between sockets (B4/7) 3 and (B4/7) 1
- Switch on ignition.
Specified value

- Voltage [ 4.8...5.3 ] V
Question

- Is the measurement value OK?

YES
The measurement value is OK.Possible cause and remedy

- B4/7 (Fuel pressure sensor)

NO
The measurement value is not OK.Possible cause and remedy

- Line from component N118 (Fuel pump control module) to component B4/7 (Fuel pressure sensor)

NO
The measurement value is not OK.Possible cause and remedy

- Test current consumption of component M3 (Fuel pump).
- Test delivery of component M3 (Fuel pump).
- Fuel filter with integrated pressure regulator

NO
Test fuel pressure and internal leaks of fuel system.
Figure legend

- 043Pressure gage
- 055Measuring beaker
- 069Pressure hose(119 589 04 63 00)
Test sequence

- Switch off ignition.
- Connect test pressure gauge.
- Connect socket box (126-pin) to component N3/10 (ME-SFI [ME] control unit).
- Insert bridge.:
- Bridge between sockets [3.4] 37 and (4.23) 108 of the 126-pole socket box tester.
- Switch on ignition.
- Component M3 (Fuel pump) runs.
- Warning! Insert bridge only for a short time.
Specified value

- Pressure[3.7...4.1] bar
- Pressure[4.7...5.3] bar1)
Question

- Is the measurement value OK?
1)With control unit 'Fuel pump'

- TypeR230 A 230 540 29 45

YES
The measurement value is OK.Test prerequisite

- Test pressure gage is connected.
- Coolant temperature< 40°C
Test sequence

- Switch off ignition.
- Insert bridge.:
- Bridge between sockets [3.4] 37 and (4.23) 108 of the 126-pole socket box tester.
- Switch on ignition.
- Component M3 (Fuel pump) runs.
- Switch off ignition.
- Remove bridge.
Specified value

- Pressure after 40 minutes:[> 2.6] bar
Question

- Is the measurement value OK?

YES
The measurement value is OK.Further possible causes of fault

- Test delivery of component M3 (Fuel pump).

NO
The measurement value is not OK.Possible cause and remedy

- In the event of slow pressure drop:Check components 'Y62 (Fuel injectors)'.
- In the event of rapid pressure drop:Check valve in component Fuel filter

NO
Check component B4/7 (Fuel pressure sensor). ( Engine is starting. )
Figure legend/figure

- N118 -Control unitFuel pump
- 55/1 -Fuel filter with integrated pressure regulator
- M3 -Fuel pump
- B4/7 -Pressure sensorFuel
Test sequence

- Switch off ignition.
- Detach coupling at component B4/7 (Fuel pressure sensor).
- Start engine.
Specified valueFuel pressure

- Pressure> 8 bar
Question

- Is the measurement value OK?

1.2. Test delivery of component M3 (Fuel pump).
Figure legend

- 055Measuring beaker
- a Fuel hose
Test sequence

- Switch off ignition.
- Connect socket box (126-pin) to component N3/10 (ME-SFI [ME] control unit).
- Detach coupling at component B4/7 (Fuel pressure sensor).
- Disconnect fuel hose a.
- Hold the open fuel line in measuring beaker 055.
- Insert bridge.:
- Bridge between sockets [3.4] 37 and (4.23) 108 of the 126-pole socket box tester.
- Switch on ignition.<->Component M3 (Fuel pump) runs.
Specified value

- 1 liters of fuel should flow in a maximum of 15 seconds.
Question

- Is the measurement value OK?

YES
The measurement value is OK.Possible cause and remedy

- Test current consumption of component M3 (Fuel pump).
End of test

NO
The measurement value is not OK.Possible cause and remedy

- Inspect fuel lines for restriction points (in particular pinching).
- Fuel filter
- Test current consumption of component M3 (Fuel pump).

1.3. Test current consumption of component M3 (Fuel pump).
Figure legend

- 003Multimeter
- B4/7 (Fuel pressure sensor)
- K40/5 (Rear fuse and relay module)
- K40/5kT (Fuel pump relay)
- K40/5f52 (Fuse 52)
Test prerequisite

- Carry out test only if complaint exists.
- Fuse K40/5f52 o.k.
Test sequence

- Switch off ignition.
- Connect socket box (126-pin) to component N3/10 (ME-SFI [ME] control unit).
- Detach coupling at component B4/7 (Fuel pressure sensor).
- Insert bridge.:
- Bridge between sockets [3.4] 37 and (4.23) 108 of the 126-pole socket box tester.
- Remove fuse K40/5f52 (Fuse 52) from component K40/5 (Rear fuse and relay module).
- Measure direct current with multimeter between sockets [K40/5f52]-.- and [K40/5f52] -.-
- Switch on ignition.
- Component M3 (Fuel pump) runs.
- Warning! Insert bridge only for a short time.
Specified value

- Amperage [10...16] A
Question

- Is the measurement value OK?

YES
The measurement value is OK.Further possible causes of fault

- M3 (Fuel pump)
End of test

NO
The measurement value is not OK.Possible cause and remedy

- K40/5kT (Fuel pump relay)
- Check lines from component K40/5 (Rear fuse and relay module) to component M3 (Fuel pump).
- M3 (Fuel pump)
End of test

2. Test gasoline fuel for water and diesel portions.
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.
First-aid measures

- 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.

Check proportion of water in gasoline fuel.
Test sequence

- Switch off ignition.
- Separate fuel feed hose at the fuel line and hold in a suitable measuring beaker.
- Connect socket box (126-pin) to component N3/10 (ME-SFI [ME] control unit).
- Connect socket box (35-pin) to component N3/10 (ME-SFI [ME] control unit).
- Switch on ignition.
- Insert bridge.:
- Bridge between sockets (F.2) 98 and (F.17) 113 of the 126-pole socket box tester.
- Component M3 (Fuel pump) runs.
- Drain off about 0.5 l fuel.
- Remove bridge.
Specified value

- Testing If water is present in the fuel, the fuel is cloudy.After being left for a few hours, the water settles on the bottom of the measuring beaker.
- In cases of doubt, compare the fuel drained with proper fuel.
Question

- Was the test o.k.?

YES
The test was not okay.Possible cause and remedy

- Water is present in the fuel.Replace the fuel.
End of test

NO
Check proportion of diesel in gasoline fuel.
Test sequence

- Allow a few drops of the drain fuel to drip onto a sheet of paper.
Specified value

- Testing The fuel should evaporate within a few minutes practically free of stains.If diesel portions are present in the fuel, a clearly visible oil stain remains after the gasoline has evaporated.
- In cases of doubt, compare the fuel drained with proper fuel.
Question

- Was the test o.k.?

YES
The test was okay.End of test

NO
The test was not okay.Possible cause and remedy

- Diesel is present in the gasoline fuel.Replace the fuel.
End of test

3. Check smooth running of engine via fault counter.

3. No further information available.

Test 3.1: Smooth engine running Cylinder 1-6

Test 3.2: Smooth engine running Cylinder 7-12

Test 3.3: Fault counter

3.1. Smooth engine running Cylinder 1-6
Preconditions for test

Smooth engine running Cylinder 1-6

3.2. Smooth engine running Cylinder 7-12
Preconditions for test

Smooth engine running Cylinder 7-12

3.3. Fault counter

4. Check self-adaptation of mixture formation.
The test prerequisites are not fulfilled.NO IDLINGNote

- Engine should be at idle speed.
Continue with button F2

5. Combustion misfirings
Warning!Communication with ECU required.

6. AR01.00-P-1200L Compression pressure

Test 6.1: AR01.00-P-1200L Compression pressure

Test 6.2: AR01.00-P-1300HV Cylinder leakage

6.1. AR01.00-P-1200L Compression pressure
Note

- WIS is not available on this system.
- It is not possible to display the requested WIS document [ ar0100p1200l ].
- You can start WIS on another system and display the WIS document by entering the document number [ ar0100p1200l ] in the 'Contents' field.

6.1. No further information available.

6.2. AR01.00-P-1300HV Cylinder leakage
Note

- WIS is not available on this system.
- It is not possible to display the requested WIS document [ ar0100p1300hv ].
- You can start WIS on another system and display the WIS document by entering the document number [ ar0100p1300hv ] in the 'Contents' field.

6.2. No further information available.