BMW E60 diesel particulate filter regeneration does not start
When does the particulate filter regeneration start on an E60 diesel?
Regeneration requires, among other things, that the coolant is above about 75 degrees, the exhaust gas is hot enough and the tank has more than 10 litres of fuel. Regeneration is easily interrupted in city driving and by accelerating.
How can driving make the regeneration succeed?
Steady driving at 80-90 km/h lets the regeneration finish best. Short trips and stop-and-go traffic are not enough. The engine temperature should rise to about 85-90 degrees after about 30 minutes of driving.
What prevents regeneration even though the driving style is right?
The temperature does not rise if one of the thermostats is faulty, and then no regenerations are carried out. Regeneration can also be blocked by a filter fault code stored in memory or a faulty intake air throttle, whose electrical parts can fail because of oil mist.
The diagnostic tool shows 'requested', is the regeneration running?
Not necessarily. 'Requested' only tells that regeneration has been requested, and it may start a couple of minutes later. Whether regeneration is running can be seen from the separate 'active' value.