Fast Idling when already warmed up

chrism42

Guest
My (56 plate) Altea FR TDI170 has developed an annoying quirk recently; it normally idles at 850rpm ish within a minute or two of starting and thereafter; but if I'm doing a fair bit of low speed driving around town, it soon decides it would rather idle at 1000rpm. As soon as I get out of town, it quickly reverts to 850rpm. Any suggestions?
 

seatfang

Active Member
Sep 7, 2010
17
1
Posibly the ECU is triggering a regen of the DPF ? I assume yours has a DPF.

The engine usually idles at a higher RPM when a regen is in progress. Or at least mine does.
 

chrism42

Guest
Yes, it does have a DPF. How often would you expect regenning (whatever that is :) ) to occur. It it normal?
 

seatfang

Active Member
Sep 7, 2010
17
1
Depends what type of journeys you make . If you do a lot of short journeys then the ECU will try to regen the DPF a lot more often.

Do you get the DPF warning light on the dash at all(Check the manual ) ?
 

chrism42

Guest
Thanks, seatfang, this is a whole new area I knew nothing about! But after a bit of googling I know what regenning the DPF is now... No, the DPF/emissions light has never come on, but the fast idling now makes sense so I'll relax for now.
Cheers
Chris
 
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