Intermittent high idle


Registered User
Hi all
I have noticed my vehicle idling high 1000-1100 randomly even when cold I seem to have noticed it since having the cam belt and water pump changed. They say that would not cause that problem any input would be appreciated

car is a 2015 a3 2.0tdi 150 CRLB engine I believe ?



Registered User
High idle can be caused by low battery voltage. When then voltage is low the higher idle increases the charge rate whilst idling.
Have a battery test done to test battery.

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Registered User
Thank you for your replies. I have checked with vcds and it states there is no regen taking place seems to be after cam belt change. It’s not a massive issue just annoying



Registered User
Check for vacuum leaks. Timing belt job can disturb loads of other bits. failing that check the readings on maf/map sensors while it’s running and see if there’s any strange readings. Sensors can fail without codes as the dodgy readings are still within normal tolerances.


Bronze Supporter
I have CRLB also noticed this. I put down to dpf or battery.
If been driving for while and come to a stop and still at 1000rpm i find letting idle for min or two, then blipping to about 1200 or 1300 for sec seems to go back down too normal idle speed.

Part from that how finding/liking your crlb 150 engine?


Registered User
VCDS Map User
Gold Supporter
I had not just a battery low warning but a battery critically low warning - idle speed was normal.