# 16806 - Main Catalyst; Bank 1: Efficiency Below Threshold



## Kraftw3rkJetta (Sep 29, 2006)

Ok, I did some searching and most seem to say it's the catalytic convertor gone bad, but could also be either 02 sensors. How can I tell before I go spending a lot of money throwing parts at the car trying to fix this? My car is a 2.0 MK4 with AEG engine code. 
I also wanted to note, for a few weeks my car had been misfiring a lot in damp and rainy weather due to my plug wires being shot. I replaced the plug wires last week, cleared any codes, and now the CEL comes on with this new code 16806 a few days ago. 


_Modified by Kraftw3rkJetta at 10:34 AM 6-13-2009_


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## Uwe (Jan 16, 2000)

*Re: 16806 - Main Catalyst; Bank 1: Efficiency Below Threshold (Kraftw3rkJetta)*

Not conclusive by any means, but the reason that misfire detection was mandated with the OBD-II regs in 1996 is that misfires kill catalysts....
-Uwe-


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## Kraftw3rkJetta (Sep 29, 2006)

*Re: 16806 - Main Catalyst; Bank 1: Efficiency Below Threshold (Uwe)*

that's what I was thinking, that maybe running the car with it misfiring like that wrecked the cat.


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## Slimjimmn (Apr 8, 2006)

*Re: 16806 - Main Catalyst; Bank 1: Efficiency Below Threshold (Kraftw3rkJetta)*

aeg engine codes have a 12yr 120k miles extended cat warranty through vw


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## Kraftw3rkJetta (Sep 29, 2006)

*Re: 16806 - Main Catalyst; Bank 1: Efficiency Below Threshold (Slimjimmn)*


_Quote, originally posted by *Slimjimmn* »_aeg engine codes have a 12yr 120k miles extended cat warranty through vw

Good to know! Actually today I had to clear my airbag code (i think I finally fixed it, found a couple of broken wires under my seat and soldered them together) so I cleared the engine code too, and so far the CEL hasn't come back on yet. Probably will, but if it does I will call the stealership and see if the the cat is covered.


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## OhioDubs (Sep 19, 2008)

*Re: 16806 - Main Catalyst; Bank 1: Efficiency Below Threshold (Slimjimmn)*


_Quote, originally posted by *Slimjimmn* »_aeg engine codes have a 12yr 120k miles extended cat warranty through vw

Do you have a Tech Bulletin number on this? Im not sure but I thought it was only other 2.0l like AZH for a 10 year 100k warranty extension.


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## P08854 (Jun 2, 2009)

i have a 99 jetta vr6 with 99.5k on the engine... getting a 16806 in combo with 17988 for throttle actuater B1 fault... first - does anyone know if this is covered under vw warranty? and second - which do i need to replace the CAT or the O2 sensor or both? any idea where i can get them real cheap? thanks guys.


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## dana vw tech (Sep 20, 2005)

*Re: (P08854)*

The VR6 did not have any warranty extensions on converters. 
There is a recall that may need done on your vehicle. It is a ECM update regarding Cat. efficiency and O2s inactivity Dtcs.
You can call your local dealer or IM me the VIN if you want to see if it has been done.
Your Throttle Actuator fault is not related to the recall.


_Modified by dana vw tech at 9:39 PM 7-29-2009_


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## P08854 (Jun 2, 2009)

dana - thanks for the quick reply... would you by any chance know how i can get my hands on the ECM update? is this something that the vw dealer will fix free of charge for me? again, i appreciate your assistance.


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## dana vw tech (Sep 20, 2005)

*Re: (P08854)*

Call your local dealer or IM me the VIN if you want to see if it has been done. 
This has to be done at a VW Dealer and yes it would be free if it hasn't already been done.


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## VgRt6 (Mar 8, 2002)

*Re: (dana vw tech)*

The update is called the N7 Emissions Service Action.


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## trbo-4 (Jul 28, 2001)

*Re: (VgRt6)*

I know I am bumping an old post, but I am geting this code and am pretty sure its the cat because I can hear it rattling. My car has 189k miles on it (1999 Mk4 2.0) so I assume its out of warranty. If i get the cat replaced and clear the code with a vag com does anything else need to be done? I need to get it to pass emissions.


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## [email protected] (Feb 16, 2007)

You will need to set readiness. VCDS has the AEG readiness procedure built in. 
Btw my AEG has the same rattling problem. 162,000 miles.


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## trbo-4 (Jul 28, 2001)

*Re: ([email protected])*

Thank you. http://****************.com/smile/emthup.gif


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## harmankardon35 (Sep 16, 2009)

funny you pulled up an old thread, because i just got the same problem. Out of nowhere I got this code (catalyst below threshold) and a few others (i wish i would have remembered before i cleared them...but it was something along the lines of 'slow response' and 'low input' on one of the sensors, forget which one! maf or oxygen i think) Anyway it was just before i had to go for an emissions test and long behold it passed (but the NOPPM limit here is 510 and the reading was 510, so at the limit) I have a receipt here from the previous owner that says it had a new cat installed 2 years ago (40 k miles ago) , should i be replacing the downstream o2 sensor?


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## BIGJ541 (Dec 1, 2012)

Talk about old treads Iam at 200,000 just poped this code . Probably the cat from what ive read .. rattle here too .


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