Strange things happened to my TDi today

[Digiman]

Today I had a strange thing happen to my TDi. I just came home from work (about 5 miles) and when I arrived home and put the car in neutral I noticed that the idling speed was up around 950 rpm and the fans were running. All fluid levels look OK. Over the last couple of weeks I have been mainly doing town driving.

I believe I read somewhere that the engine management system will increase the idling speed if it thinks the DPF is starting to get clogged up.

Anybody got any ideas.

[youvebinaced]

If your ever unsure just take it in to your vw dealer n get them to have a look at it, because you don't want to be in the position that your warrenty has run out on something that has gone wrong when you could have had it done for free earlier on.

[maisbitt]

Almost definitely the DPF - when you're not doing enough sustained high revs driving for a passive burn-off of the particulates, the engine management will make the car run in such a way to increase the exhaust temp to allow a forced regeneration on the DPF. The biggest giveaway for this will be idling at about 1000rpm as opposed to 800rpm normally, and the accelerator response may feel a bit lumpy from 1200 - 2000rpm. Used to happen loads in my 170TDI PD Golf, doesn't happen much in my Scirocco now.

The DPF likes to have a 10 min spell of sustained driving at 1800 - 2500rpm to burn off the particulates passively, if you're not doing any dual carriageway/motorway miles then the forced regeneration will happen a few times a week.