fault code 16891 Idle control system

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scotspie501
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fault code 16891 Idle control system

Post by scotspie501 »

Hi All

I have a error code 16891 Idle control system RPM higher than expected

I can clear it with vag com lite but once my son drives the car comes back
scotspie501
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Re: fault code 16891 Idle control system

Post by scotspie501 »

Hi All

I took some Carb cleaner to the idle valve and yes it was dirty ,

no code returned
scotspie501
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Re: fault code 16891 Idle control system

Post by scotspie501 »

Hi all

I was wrong code came back do you need to program a new throttle valve module

or can I just fit it
RUM4MO
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Re: fault code 16891 Idle control system

Post by RUM4MO »

You know, this is to me still an unknown!

Many people will say that you MUST perform Basic Settings on the Throttle Body so that the engine's ECU gets to know and save the fully open and fully closed feedback values, but others will say "just switch on the ignition, don't start the engine, and wait a few minutes - by then the system will have performed a re-cal so all will be okay".
My wife now has a 2015 VW Polo 1.2TSI 110PS and certainly it performs some sort of TB re-cal just after switch off and again if allowed to just after the ignition is left on without running the engine.
From my previous use of a car of the age your son's Polo is, I have sprayed carb cleaner into the TB in a bid to "freshen" it up, then run Basic Settings on the TB every other year at service time, I always planned to leave the electrical connector plugged in just in case I ended up suffering a failed Basic Settings run.
scotspie501
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Re: fault code 16891 Idle control system

Post by scotspie501 »

Hi all

do you know the best place to but a new throttle body as it keeps bringing error code but no limp mode up

thanks for your info
johntheo2
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Re: fault code 16891 Idle control system

Post by johntheo2 »

I replaced the TB on a 19 year old Bora "cable" operated one and didn't do any adaptation, it settled down to its normal idling speed of 730 RPM after a few miles. I just replaced it with a £35 breakers yard one with no adaptation don't know if a new TB needs it though.
I wouldn't rush off just yet though, it may be worth switching on the ignition and holding down the accelerator with a block of wood or get someone to keep it depressed and gently clean just inside the TB with a bit of cloth soaked in carbon cleaner where the butterfly seats, (if not already done). Also check any vacuum connections especially the "plasticky" one(s) like the one to the brake servo, these can be cracked and easily missed. Also could possibly be the PCV valve.
scotspie501
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Re: fault code 16891 Idle control system

Post by scotspie501 »

Hi John

cleaned throttle body with carb clean and fault came back after a few runs
same error code ,me maybe get a TB and try it before the winter

will keep you informed
CaveDweller02
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Re: fault code 16891 Idle control system

Post by CaveDweller02 »

An alert that the RPM is higher than expected when your son's driven the car. I bet my first Mini would have flagged up a similar alert if it had the same sort of warning system too!
CaveDweller02
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Re: fault code 16891 Idle control system

Post by CaveDweller02 »

An alert that the RPM is higher than expected when your son's driven the car. I bet my first Mini would have flagged up a similar alert if it had the same sort of warning system too!
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