quattro Digest, Vol 128, Issue 1

thejimrose thejimrose at gmail.com
Mon Jun 2 12:45:58 PDT 2014

quick google search shows knock sensors listed for an 09 a4. so yes?

why are you worried about knock?  if the ecu senses knock it will adjust to
compensate. if you need to worry about it, it will store a code / fire a
CEL. modern ecu's are  smarter than any of us and will let you know if/when
there are issues. they are also impossibly complex in terms of what / how /
how often/ how variable [self-learning] they monitor and adjust. that said
any of the obd2 code reader / smartphone doodads could give you insight to
codes and let you monitor signals. vagcom is the no brainer for the vag
cars. imo a boost / vac gauge is still the best single indicator of how the
cars running. there are a few nice obd monitor solutions if you want
something permanent / geeky. i just bought one of these for my suby to keep
an eye on boost, etc.

one thing you should worry about is carbon buildup. DI engines tend to
carbon pretty badly since there's no fuel wash to dissolve it. make it part
of the 30-40k service list to have looked at / cleaned.

> ---------- Forwarded message ----------
> From: Nick Lawrence <nick at beol.net>
> To: quattro at audifans.com
> Cc:
> Date: Mon, 02 Jun 2014 14:51:04 -0400
> Subject: 2009 A4 TSI
> Hello,
> I moved up about 2 decades in Audi technology and am getting a 2009 A4
> Avant TSI.   I would like to know If there are knock sensors (most likely),
> and how they function.
> Meaning if there is knock does the computer make changes and if it
> continues to knock create a stored code?
> Is there ever any driver visible indicator that there is engine knock?
> Any insight will be appreciated.
> Nick   central Ohio

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