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Misfire, cylinder-selective



NOTE 1

The fault types have special significance for misfires:

Fault type "Implausible signal": exhaust-related fault after engine start-
up

Fault type "Below limit value": exhaust-related during the journey

Fault type "Above limit value": fault damaging to catalytic converter





NOTE 2

The totals error P0300 is always entered in addition to any other
misfires. The misfires may have occurred in one or several cylinders.



The misfire detection function can blocthe fuel injection for the
remainder of the driving cycle after a permanent misfire is detected on
the cylinder in question. Misfire detection remains active.





Diagnostic conditions



Engine running

Engine load > 4 to 25% depending on engine speed

Intake air temperature > -30°C (-22 °F)

No fault in crankshaft sensor

Testing for misfires while driving: smooth road surface conditions (= no
bumpy track)





Possible fault causes



If a misfire only occurs on one cylinder:

A Electric fault in control line between DME and ignition coil

A Sparplug connector faulty

A Ignition coil faulty

A Sparplug faulty

A Secondary air


When misfires occur on both banks:

A Tanempty

A An engine-blocheater is used

A Secondary air

A Exhaust system blocked/narrowed

A Foreign bodies in intake tract, this can lead to sporadic misfires
on changing cylinders.





A Mechanical or electrical fault in injection valve

A Valve seat or valve faulty

A Valve lift control faulty

A Exhaust system blocked/narrowed

A Foreign bodies in intake tract, this can lead to sporadic misfires
on changing cylinders.



When misfires occur on the banks:

A Electric fault or loose contact in the control line to solenoid valve
of camshaft adjustment

A Solenoid valve of camshaft adjustment electrically/mechanically
faulty or clogged

A Hall sender rotor (sensor wheel) faulty/kinked

A Secondary air

A Intake camshaft adjustment too slow

A Intake camshaft timing incorrect

A Exhaust camshaft timing incorrect

A Fault in the valve lift control

A Oxygen sensor faulty (also: loose contact in wiring harness) ^

A Exhaust system blocked/narrowed

A Foreign bodies in intake tract, this can lead to sporadic misfires
on changing cylinders.
 
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