Need help here....16804-catalyst system efficiency bellow threshold....seconday air injection failed

[Dubbin_vr6]

I got 1 DTC's that I have been trying to figure out for the longest time now....
16804-Catalyst system efficiency below threshold (Bank 1)
35-00--

And I have been testing the readiness ever since and finally today I logged, a fail....
it says readiness status=00001000
seconday air injection : failed or incomplete....
can anyone help me with this info?

Mark

[JM1681]

Does your intake allow for the secondary air pump? If not, I've heard that could attest to the "air injection" code

[the wolf]

i had the 16804 code & one more...faulty cat was the reason, replaced under emissions warranty!

[Dubbin_vr6]

Quote, originally posted by JM1681 »

Does your intake allow for the secondary air pump? If not, I've heard that could attest to the "air injection" code

I do not know the answer to this question....Its a 2001 jetta 1.8t AWW...

[Dubbin_vr6]

Quote, originally posted by the wolf »

i had the 16804 code & one more...faulty cat was the reason, replaced under emissions warranty!

yes but I passed the readiness test exept for the secondary injection system....
what is the secondary air injection system?

Mark

[RonN]

16804 is caused primarily by most of us having aftermarket exhaust. o2 sensor #1 is cooling off too fast causing the code to trigger the check engine light.

[Dubbin_vr6]

the exhaust system is completely stock....all the car has is a chip
MArk

[Dubbin_vr6]

help

[JettaRed]

I had it (or was it 16803?). I replaced the O2 sensor (approx. $30). 021906262B for the six wire (front) and 06A906262Q for the 4 wire rear. You can also use 06A906262Q for the front (bank 1) if it's 4 wire.

the cheapest place is http://www.1stvwparts.com

[Dubbin_vr6]

Quote, originally posted by JettaRed »

I had it (or was it 16803?). I replaced the O2 sensor (approx. $30). 021906262B for the six wire (front) and 06A906262Q for the 4 wire rear. You can also use 06A906262Q for the front (bank 1) if it's 4 wire. the cheapest place is http://www.1stvwparts.com

had you passed the emissions tesT?
thanks
Mark

[Dubbin_vr6]

help guys

[Nonlinear Optics]

Have you tried clearing the code? How long did it take to return?

[Dubbin_vr6]

I clear it and it comes back in 2-3 days....depending on how long I drive

Mark

[Junk T.I.]

Mark

the cat fault is as it seems, your cat is probably bad.... and needs replacement

which is covered under the 8/80 emissions warranty as long as you have replaced plugs around 40k miles( I am not sure if you are that high in mileage)

as for the secondary air incorrect flow.... 99.9% of the time its a broken vac hose..... but it could be a bad air pump, bad Combi valveor whatever.....

[JettaRed]

My CEL was also coming on about twice a week. All the readiness codes were PASSED, but I still got the DTC. I swapped the before cat O2 sensor, but it hasn't been long enough to see if it comes back.

Again, the bentley says to replace the O2 sensor; it doesn't say anything about replacing the cat. Plus if the problem is BEFORE the cat (i.e., Bank 1), then why would you replace the cat?

[Dubbin_vr6]

Quote, originally posted by JettaRed »

My CEL was also coming on about twice a week. All the readiness codes were PASSED, but I still got the DTC. I swapped the before cat O2 sensor, but it hasn't been long enough to see if it comes back. Again, the bentley says to replace the O2 sensor; it doesn't say anything about replacing the cat. Plus if the problem is BEFORE the cat (i.e., Bank 1), then why would you replace the cat?

what I don't understand is how can I figure out what to change....do I just start changing sensors randomly and hope that the dtc doesn't come back?

thanks for your help guys...VERY APPRECIATED

Mark

[JettaRed]

There is only one precat sensor and one post-cat sensor. Precat is Bank 1 and post-cat is Bank 2. The DTC is pretty specific as to which O2 sensor has the problem.

[Dubbin_vr6]

Quote, originally posted by JettaRed »

There is only one precat sensor and one post-cat sensor. Precat is Bank 1 and post-cat is Bank 2. The DTC is pretty specific as to which O2 sensor has the problem.

I'll change that sensor when I get a chance...is the sensor, the part number you posted above?

thanks
MArk

[Dubbin_vr6]

any other insight?

[Dubbin_vr6]

up

[JettaRed]

Quote, originally posted by Dubbin_vr6 »

I'll change that sensor when I get a chance...is the sensor, the part number you posted above? thanks MArk

Actually, those part numbers were for an AWP engine. The AWW engine uses the same for front and rear. You need part number 06A906262Q, which is only $16.22 from http://www.1stvwparts.com. (List is $21.63; so it may be cheaper to pay list from the dealer.)

[Dubbin_vr6]

Quote, originally posted by JettaRed »

Actually, those part numbers were for an AWP engine. The AWW engine uses the same for front and rear. You need part number 06A906262Q, which is only $16.22 from http://www.1stvwparts.com. (List is $21.63; so it may be cheaper to pay list from the dealer.)

thanks for your help!
Mark

[Junk T.I.]

Quote, originally posted by JettaRed »

There is only one precat sensor and one post-cat sensor. Precat is Bank 1 and post-cat is Bank 2. The DTC is pretty specific as to which O2 sensor has the problem.

just to clear this up.....

on a 1.8T there is no bank 2....\
what you will see is bank 1 sensor 1 or bank 1 sensor 2

bank 1 sensor 1 is precat

bank 1 sensor 2 is post

only cars such as V6 style cars that have dual exhausts will have more than 1 bank...

[JettaRed]

My error. thanks for the clarification.

[Dubbin_vr6]

Quote, originally posted by Junk T.I. »

just to clear this up..... on a 1.8T there is no bank 2....\ what you will see is bank 1 sensor 1 or bank 1 sensor 2 bank 1 sensor 1 is precat bank 1 sensor 2 is post only cars such as V6 style cars that have dual exhausts will have more than 1 bank...

where does it say wihich sensor it is

thanks
Mark

[JettaRed]

Quote, originally posted by Dubbin_vr6 »

where does it say wihich sensor it is thanks Mark

Actually, when you search on 16804 in the Bentley CD, it identifies the sensor as being pre-cat.

[Junk T.I.]

Quote, originally posted by JettaRed »

My error. thanks for the clarification.

no sweat

[Dubbin_vr6]

Quote, originally posted by JettaRed »

Actually, when you search on 16804 in the Bentley CD, it identifies the sensor as being pre-cat.

ok thanks

I don't have the bentley cd yet!

Mark

[JettaRed]

Quote, originally posted by Dubbin_vr6 »

ok thanks I don't have the bentley cd yet! Mark

three things you should have:

1. A Bentley CD
2. A VAG-COM
3. A copy of the ETKA (electronic parts catalog--search ETKA on ebay)

[Dubbin_vr6]

Quote, originally posted by JettaRed »

three things you should have: 1. A Bentley CD 2. A VAG-COM 3. A copy of the ETKA (electronic parts catalog--search ETKA on ebay)

yeah I'll get it...just give me chance....

[JettaRed]

Well, I got the same code again after replacing my pre-cat o2 sensor. I'm going to order a post-cat sensor (the cheaper one).

[Dubbin_vr6]

I don't think this code is refering to any kind of sensor....like Junk T.I.
was telling me....If it were a sensor...it would say S1 or S2....I know because I vagged my buddies vr6 today and It said B1 S2...
I think the code I am getting is the cat itself.....especially that latelly I have been getting more than a few missfires even though the coils are brang new....

I'll try and get the cat changed...it under warraty anyways...and see what happenes from there...

thanks
Mark

[JettaRed]

Quote, originally posted by Dubbin_vr6 »

I don't think this code is refering to any kind of sensor....like Junk T.I. was telling me....If it were a sensor...it would say S1 or S2....I know because I vagged my buddies vr6 today and It said B1 S2... I think the code I am getting is the cat itself.....especially that latelly I have been getting more than a few missfires even though the coils are brang new.... I'll try and get the cat changed...it under warraty anyways...and see what happenes from there... thanks Mark

Well, if you can't or they want too much, I have my stock downpipe and cat I might sell. (or you can place a "want to buy" ad in the classifieds.)

BTW, I assume you have your stock downpipe on.

[Dubbin_vr6]

yeah I have the stock downpipe...I have 70 000kms...on my car the cat is warratied until 160 000kms so it should be under warraty

Mark

[JettaRed]

I called the dealer to double-check on the part number and it is the Q part. They also have it for $27. The parts guys also "thought" there was a tech bulletin out on it, but couldn't confirm it.

The interesting thing is whenever there is a problem with a failing part, the price drops dramatically. In this case, it seems VW is having a problem with o2 sensors.