P0303
P0303Diagnostic information - DME V8 DFI
Misfire detection Cylinder X
NOTE:
- The fault P0300 >>Misfire totals fault<< indicates that an exhaust-relevant misfire has been detected for at least 1 cylinder.
- An initial indication appears because the relevant cylinder(s) is/are also stored.
NOTE:
- Diagnosis detects uneven running for the specified cylinder.
- Uneven running is calculated from the expected and actual crankshaft acceleration due to combustion.
- Uneven running is interpreted as a misfire or valve lift fault, depending on type.
NOTE:
- A cycle of 1,000 crankshaft revolutions is evaluated for exhaust-relevant misfires.
- The cycle is 200 revolutions for misfiring rates that will damage the catalytic converter.
- The misfiring rates are compared with a threshold value.
- If the misfiring rate is greater than the threshold value, the fault is set.
- The >>Check Engine<< warning light flashes if the misfiring rate has the potential to cause permanent catalytic converter damage.
NOTE:
- It is possible that only one cylinder (or the cylinders of one bank) has/have exceeded the uneven running threshold for a fault entry.
- However, other cylinders may also be just below the level which would result in a fault entry.
NOTE:
- Sensor wheel adaptation is necessary only after control unit programming.
- It is only when this is done that misfires can be reliably detected by the DFI.
- For this purpose, it is necessary to accelerate three times in second gear and then to allow the vehicle to coast to a stop without changing gear, braking or accelerating (overrun fuel cutoff phase).
- It is possible to establish whether adaptation has been performed by reading out [[Adaptation status]] under [[Actual values]] in the PIWIS Tester.
Diagnostic conditions
- Engine temperature > -20 °C (-4 °F)
- Engine speed > 400 rpm 6,700 rpm
- No overrun condition
- No crankshaft sensor fault P0335, P0336, P0371 or P0373 detected
Possible fault cause
- Use of an engine-block heater
- Lines, power or ground supply faulty for electrical components listed below (loose contact, oxidation, etc.)
- Lines, power or ground supply faulty for DME (DFI) control unit (loose contact, oxidation, etc.)
- Wrong spark plug(s) installed
- Mechanical or electrical fault in spark plug(s)
- Bar ignition module(s) faulty
- Power or ground supply faulty
- Tank filled with incorrect fuel quality
- Tank driven empty
- Water in tank
- Fuel filter dirty/blocked
- Mechanical fault in predelivery fuel pump
- Mechanical fault in high-pressure fuel pump
- Mechanical or electrical fault in fuel injector(s)
- Oxygen sensor faulty
- Exhaust system faulty - flow severely restricted
- Muffler blocked / faulty
- Kink in exhaust pipe
- Catalytic converter damage
- Leak in intake-air distributor
- Foreign matter in intake-air distributor
- Fault in adjustment of intake camshaft timing (VarioCam)
- Exhaust camshaft timing incorrect
- Hydraulic tappet faulty
- Valve lift control faulty
- Valve seat or valve faulty
- Mechanical engine fault