# Today's fault codes are :



## gogs (Dec 22, 2010)

I've cleared these codes today, can anyone advise if this is an expensive fix?

18702 - oxogen (lambda) sensor signal b1 S2 too lean P2270-001 upper limit exceeded intermittent 
16804 - catalyst system bank 1 efficiency below threshold P0420-001 upper limit exceeded


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## gogs (Dec 22, 2010)

Anyone?


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## V6RUL (May 28, 2009)

Take her out for a thrash.
Looks like post cat to me which is just a monitoring sensor.
Maybe just some crap on the sensor face that needs burning off.
I've removed my post sensors and had them mapped out.
Steve


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## gogs (Dec 22, 2010)

Thanks Steve, I'll give it a decent blast and see, I'm hoping its not the cat that's gone!


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## V6RUL (May 28, 2009)

Fingers crossed.
Steve


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## Skeee (Jun 9, 2009)

If your Readiness Bits are all zero then can't be all that bad.

Post Cat Lambda could be an exhaust leak or http://wiki.ross-tech.com/wiki/index.ph ... 420/001056

 16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold
Possible Causes
Leakage in Intake and/or Exhaust System
Catalyst faulty
Oxygen Sensor(s) faulty
Oxygen Sensor(s) Control faulty 
Possible Solutions
Check Intake and Exhaust System for Leaks
Check Catalyst
Check Oxygen Sensor(s)
Check Oxygen Sensor(s) Control
Perform Oxygen Sensor(s) Aging Check 
Special Notes
For 1.8T's experiencing this fault code, this thread may be useful: http://forums.vwvortex.com/zerothread?id=663057  

Quote Mine is cause by cruising below 2500 rpm for too long with a 3" HF cat.

Another quote:- Cat efficencly below threshold is usually an exhaust leak by the post O2 sensor, and it's usually at the clamp that connects the down pipe to the rest of the exhaust. If there is even a small leak, then under deacceleration there is a pressure gradient that is created. And, then the air outside is then "sucked" back in to the exhaust system for a split second. 

Also 18702 490E P2270 lambda probe 2-lean bank 1 signal too lean. *
vag-codes.info/files/vas-5051-error-codes.pdf*


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## gogs (Dec 22, 2010)

That dosent sound good Skeee :-(


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## Skeee (Jun 9, 2009)

Depends how frequent/often the code occurs.

If all the readiness bits are at zero a few days after you clear these two codes then unless you get a MIL I'd ignore these two codes.
And obviously your MOT emission passes of course. :roll:


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## james 91 (Jul 12, 2011)

What cat are you running?


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## gogs (Dec 22, 2010)

Thanks Skeee,only passed its mot last month!

James it's on the oem cat just now


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## gogs (Dec 22, 2010)

Skeee said:


> Depends how frequent/often the code occurs.
> 
> If all the readiness bits are at zero a few days after you clear these two codes then unless you get a MIL I'd ignore these two codes.
> And obviously your MOT emission passes of course. :roll:


How do I check the readiness bits Skeee?


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## Skeee (Jun 9, 2009)

Them eight zeros below the engine fault are the readiness bits.

Last one (bit eight) is Lambda. (*Cat Converters*)

When you clear any Engine codes the readiness bits all set to fail (all 1s) until you perform certain tests that clear them.

e.g. drive above 2500 revs for more than 1 minute etc etc

Some bits stay at zero as not applicable to the TT. ie I get 0110 0101 after reset- see below.

READINESS Bit
1 Ex Gas Recirc ------ _-Not Tested-_
2 O2 Heating
3 02 Sensor
4 Air con -_----------- -Not Tested-_
5 Secondary Air injection ---_- -Not Tested-_
6 Evaporative Emissions
7 Cat Heating ----_-------- -Not Tested-_
8 Cat Converters


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## gogs (Dec 22, 2010)

Thanks Skeee, so with them all sitting at 0 does that mean its ok? I've been out in the car again this afternoon and so far no MIL light


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## Skeee (Jun 9, 2009)

All zero is good as it's all passed.

The 16804 for Post Cat Sensor can be ignored (obviously have a look for hose leaks and listen for exhaust leaks) if the cat passes the MOT.
The only problem is if it does put the MIL on and you don't clear it, then the MIL may be masking another serious engine problem. So never a good idea to drive with the MIL on for too long.


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## gogs (Dec 22, 2010)

Thanks Skeee, I usually scan the car ASAP if I get any MIL lights, because I don't want to end up with any serious issues due to me ignoring one :-o


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## V6RUL (May 28, 2009)

Don't think it will be an exhaust leak on the Vee, unless something is cracked, as I'm sure exhaust fixings pre cat are flanges and gaskets.
Steve


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## james 91 (Jul 12, 2011)

gogs said:


> James it's on the oem cat just now


In that case your possible problems are:
- Rich mixture (Check fuel trims in Group 032)
- Faulty 02 sensor
- Faulty cat

You will need to do some testing with VAG-com to test the last two.


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## gogs (Dec 22, 2010)

Thanks James, I'll run a scan again, do you know what Module etc I need to go into to get the info on the last 2?

Would having the VTDA induction set up cause this kind of issue?


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## Skeee (Jun 9, 2009)

viewtopic.php?f=2&t=276355

The Lambda (O2 Sensor)) Ageing Test is in the Tweakers Guide by WAK, see the link above.

ECU Measuring Blocks 30, 31, 32 & 33.


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## gogs (Dec 22, 2010)

Thanks again Skeee


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## james 91 (Jul 12, 2011)

gogs said:


> Thanks James, I'll run a scan again, do you know what Module etc I need to go into to get the info on the last 2?
> 
> Would having the VTDA induction set up cause this kind of issue?


No the Induction kit wouldn't cause the codes. Out of interest do you have an engine light on?

To check the Lambda probe after the Catalyst ensure coolant is >80 degrees and connect VAG-Com. Enter the 
"01-Engine" module and then "04-Basic setting". Read Group 030 - with the engine idling Value 1 should read 111, and value 2 110 at least once.it may take a few minutes to achieve this.

Next enter group 037 and hold the engine speed at 2000rpm. value 2 should read 0.1-0.95 V, some fluctuation is permissible, but not considerable fluctuations. Value 3 should read less than 0.02 and value 3 should read Syst. OK.

Check these and post them up!


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## gogs (Dec 22, 2010)

Thanks James, I'll try this tomorrow night, no engine light on, it was just the emissions light that came on


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## gogs (Dec 22, 2010)

Hi James I've run the checks and recorded a short video however I can't seem to upload it :-(
I've uploaded it to photobucket but when I upload it to the forum it can't be viewed !


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## james 91 (Jul 12, 2011)

Just stick it on YouTube and post the link mate


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## gogs (Dec 22, 2010)

james 91 said:


> gogs said:
> 
> 
> > Thanks James, I'll run a scan again, do you know what Module etc I need to go into to get the info on the last 2?
> ...


Group 030 value one fluctuated between 011 and 111, value two sat bang on 110

Group 037 value two did not rise above 0.34 value three read 0.004 next one along read test off


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## gogs (Dec 22, 2010)

PM sent James


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## gogs (Dec 22, 2010)

PM sent James ;-)


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## Typhhon (Oct 28, 2006)

Secondary Air Pump?

Since I removed mine these codes (and their mates) pop up every so often despite a mass of resistors....

Going to have APS map 'em out sometime


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## gogs (Dec 22, 2010)

Would the secondary air pump cause these faults ?


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## Typhhon (Oct 28, 2006)

Mine did and all the parts checked out fine...
Also had 
16804 - 
16814 - 
and obviously.....
17831 -
17819 -


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## gogs (Dec 22, 2010)

Are there any other checks I can carry out for the secondary air pump?

The Lambda sensor readings seem to be off in reading one, fluctuating between 011 & 111, James mentioned this should read 111 pretty much all the time !


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## james 91 (Jul 12, 2011)

Gogs, The SAI wouldn't cause the codes you've got in isolation, it would log codes associated with the SAI itself too which you don't have.

Your post-cat lambda sensor looks to be fine from the readings, Group 30 zone 2 should read 110 which is its status value so that's fine. Group 037 shows it's voltage and correction value which are in specified limits so it looks fine. To make sure if you read group 037 in basic functions again, set the revs to 2000rpm and press the Basic Settings: "On/Off/Next" button and check the value in zone 4, If it reads "Syst.OK" then its fine and your Cat is likely the cause. If it reads "Syst. n OK" take it for a blast and repeat, if still "Syst. n. OK" then the sensor is faulty.


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## gogs (Dec 22, 2010)

Thanks James will give it a shot tonight, I do hope its not the cat :-(


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## Claire_erialc (Feb 28, 2013)

Every time my engine management light comes on I have different fault code readings..they get checked out and are all fine. Codes all wiped, car is fine for a few days..then back to se drama..this time it's also cutting out. Apparently it's the automatic cut-off after a bump but it always happens whilst driving on smooth flat road..no bumps or potholes..any ideas?


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## V6RUL (May 28, 2009)

Claire_erialc said:


> Every time my engine management light comes on I have different fault code readings..they get checked out and are all fine. Codes all wiped, car is fine for a few days..then back to se drama..this time it's also cutting out. Apparently it's the automatic cut-off after a bump but it always happens whilst driving on smooth flat road..no bumps or potholes..any ideas?


Can you explain what the automatic cut off is and what activates it.
What happens when it activates?
Steve


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## Claire_erialc (Feb 28, 2013)

V6RUL said:


> Claire_erialc said:
> 
> 
> > Every time my engine management light comes on I have different fault code readings..they get checked out and are all fine. Codes all wiped, car is fine for a few days..then back to se drama..this time it's also cutting out. Apparently it's the automatic cut-off after a bump but it always happens whilst driving on smooth flat road..no bumps or potholes..any ideas?
> ...


Sorry..I don't know correct technical talk  but..garage told me last time that the computer thinks the car has had a crash so cuts off the engine..it's just like I've stalled, can start the car again but same will keep happening. Until the fault code is wiped then the car runs fine


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## Skeee (Jun 9, 2009)

Hi Claire,
next time it happens ask the garage (or whoever looks at it) to write down all the code numbers or better still ask for a print out.

There may also be a TTF member near you who's willing to scan it.

Sounds like this:- viewtopic.php?f=2&t=162132
but without codes, it could be anything?


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## Claire_erialc (Feb 28, 2013)

Thank you!! This other person is having the exact same problem as me!


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## Marco34 (Apr 5, 2009)

HI Gordon

I've had these in the past, in fact I only know about them because the MIL comes on. All my problems have been down to the connectors under the car. They are in a stupid place where water can get at them. Mine were quite corroded. I cleaned them all with circuit board cleaner then filled them with dialectric grease and the problem as not returned. It's easy to jump to lambda sensors being the issue but I would start there. There's a black box bolted to the bottom of the car, you can see it from the drivers side mid way down. Easier when on ramps.

Cheers
Marc


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## gogs (Dec 22, 2010)

Hi Marc,

That would make sense, I've not had the light on again and not had a chance to rescan the car today as per James post, will do it tomorrow, I've seen that black box your talking anout when the cars been on the ramps for the MOT, where did you clean up the connectors ? At this black box area? Do they just plug in to the box or does it need to be opened up?

Maybe a trip to maplin's tomorrow to see if I can get the items you used


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## Marco34 (Apr 5, 2009)

Hi Gordon,
The black box is just the housing. I think two bolts hold it in. It's got air holes to allow water to escape but muck can get in. There are four connections. One for each probe. Check them and make sure all look good. 
Cheers.
Marc

Sent from my HTC Desire C using Tapatalk 2


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## gogs (Dec 22, 2010)

Hi James performed the test as you said and its come back "system ok"
See below










Is there any way to check the cat itself?
The light has not came back on and I've no further fault codes

Marco I've still to try cleaning the connectors, didn't get to it at the weekend :-(


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## gogs (Dec 22, 2010)

?


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## james 91 (Jul 12, 2011)

I wouldn't worry too much mate if it hasn't come back, could be an intermittent fault. You don't have any cooling system related fault codes do you?


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## gogs (Dec 22, 2010)

No other fault codes or warning lights at all for now!

Fingers crossed its just a one off then


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## Typhhon (Oct 28, 2006)

Cat function can be verified on an emissions tester as used for MoT's.
Just need someone who knows what the 'good readings' are to check condition.

Obviously if its toast it will show up as an MOT fail.

APS checked mine and the 'black box' when my faults appeared hence I know mine are down to the Sec Air delete.


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## gogs (Dec 22, 2010)

Just had the MOT in January and it passed with flying colours !


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## james 91 (Jul 12, 2011)

Wouldn't worry then pal, just keep an eye open for the code recurring


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## gogs (Dec 22, 2010)

Thanks James


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## gogs (Dec 22, 2010)

Well chaps, IML light on again this morning :-(
Scan performed and its the same code as before, cleared the code but not been back out in the car, think I'll try Marco's suggestion of cleaning the connectors if its dry tomorrow, any other thoughts ?


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## Marco34 (Apr 5, 2009)

gogs said:


> Well chaps, IML light on again this morning :-(
> Scan performed and its the same code as before, cleared the code but not been back out in the car, think I'll try Marco's suggestion of cleaning the connectors if its dry tomorrow, any other thoughts ?


What was your code again Gordon? Mine came on last week after a NW TT cruise but it was lashing down for 3 hours so suspect water ingress again. Been ok since. I think my car is telling me not to drive it in the wet!


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## Skeee (Jun 9, 2009)

Mine's a BAM 225 so slightly different I know but if it's any consolation I sometimes get the following after Cat sensor fails on vagcom between May and August? Not every journey just occasionally. 
But have only had one MIL in three years?
It always passes the MOT no problem.
From Sep to Apr it's always fine.
When it does happen it seems to have been when I was driving very gently on the pedals and with low revs.
Car's totally stock.

16523 - Oxygen (Lambda) Sensor B1 S2: Response too Slow
P0139 - 35-10 - - - Intermittent
Readiness: 0000 0000

16522 - Oxygen (Lambda) Sensor B1 S2: Signal too High
P0138 - 35-10 - - - Intermittent
Readiness: 0000 0001


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## Tbone (Jan 26, 2013)

Had same codes cleaned up connectors under car as marco has explained water even came out off them they were very corroded 4 months on no codes


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## gogs (Dec 22, 2010)

gogs said:


> I've cleared these codes today, can anyone advise if this is an expensive fix?
> 
> 18702 - oxogen (lambda) sensor signal b1 S2 too lean P2270-001 upper limit exceeded intermittent
> 16804 - catalyst system bank 1 efficiency below threshold P0420-001 upper limit exceeded


Hi Marc,

Code this time around was one of the above, (the 1st i think) I can't remember which now, I was that annoyed I just cleared them after the scan :-O
1st time was beginning of March this year and the 2nd today both times just cruising along at relatively low speed tbh

Ok I'll get my arse to maplins tomorrow to buy the stuff Marc mentioned, is the removal of the black cover and cleaning of the terminals a reasonably easy job?

My cars pretty much stock as well Skeee, Milltek cat back and VTDA are the only real mods


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## Tbone (Jan 26, 2013)

very easy indeed you will see the black box under the drivers side just be careful un connecting the connectors mine were corroded tight problem will be solved


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## gogs (Dec 22, 2010)

Tbone1980uk said:


> very easy indeed you will see the black box under the drivers side just be careful un connecting the connectors mine were corroded tight problem will be solved


Thanks very much, what did you use to clean up your connectors?


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## Skeee (Jun 9, 2009)

http://www.halfords.com/webapp/wcs/stor ... yId_255223

http://www.maplin.co.uk/contact-cleaner-25340

http://www.toolstation.com/shop/Automot ... 795/p81507

That's a surprise, Halfrauds is cheaper than Maplins!

I actually use IPA and dry air in a can then put a bit of Electrolube contact oil on after.


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## Tbone (Jan 26, 2013)

i must admit i only used wd40 on mine :lol: :lol:


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## gogs (Dec 22, 2010)

Thanks Skeee, I some IPA, Maplins and Halfords are next to each other in my local retail park, so either or will be good I guess, any special socket required to remove the bolts or screws that hold this black cover on?
Do you guys disconnect the battery for this job?


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## gogs (Dec 22, 2010)

I need to stock up on WD40 anyway do I'll add this to the shopping list


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## Skeee (Jun 9, 2009)

If you wipe all the WD40 off it leaves a tiny residue of oil so isn't too bad a substitute, however they now make an actual contact cleaner.

http://www.screwfix.com/p/wd-40-special ... aner/92716


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## gogs (Dec 22, 2010)

I'll see what both maplins and halfords have in stock ;-)


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## jamman (May 6, 2002)

Agree with the angry monkey use a proper elctrical contact cleaner Halfords stock it.

Good luck mate hope it's something and nothing


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## gogs (Dec 22, 2010)

Thanks James, fingers crossed, was on the verge off getting rid of it tbh :-(


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## Tbone (Jan 26, 2013)

I did change temp sensor at the same time but also had temp sensor code hope you sort it cheers mark


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## Marco34 (Apr 5, 2009)

Agree it's best to use a proper electrical cleaner as opposed to WD40. I also apply liberally dielectric grease. You can get that from maplins. That's for the internal part when the contacts meet. Also a good idea to spray the connectors once plugged with WD40 to help repel water ingress. I still got my light on, but I think it's the fact that the connectors have already taken a beating. Ideally then need replacing I think.


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## Skeee (Jun 9, 2009)

jamman said:


> Agree with the *angry monkey* use a proper elctrical contact cleaner Halfords stock it.
> Good luck mate hope it's something and nothing


http://familyguy.wikia.com/wiki/Evil_Monkey

He's not always angry.


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## jamman (May 6, 2002)

Skeee said:


> jamman said:
> 
> 
> > Agree with the *angry/evil monkey* use a proper elctrical contact cleaner Halfords stock it.
> ...


Read it all even the big words and the Angry/Evil Monkey still comes across as having issues. :wink:


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## gogs (Dec 22, 2010)

Aarrrrggghh its bloody raining :-(


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## Skeee (Jun 9, 2009)

gogs said:


> Aarrrrggghh its bloody raining :-(


But..............

It's Scotland? :lol: 
_What did you expect? :roll: _


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## gogs (Dec 22, 2010)

Thanks Skeee, sun came out for an hour there and I made the most if it 

Got the cover off and unplugged the connectors, water poured out of every connector bar one :-o
None of the connectors looked badly corroded, in fact they all looked quite new !
I dried them off, cleaned them up, dried again, applied electrical grease to the connectors, cleaned the cover up as it was pretty dirty and refitted everything, I've taken pics so will post a how to later as it seems to be quite common 
Fingers crossed this does the job


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## Skeee (Jun 9, 2009)

gogs said:


> Thanks Skeee, sun came out for an hour there and I made the most if it
> Got the cover off and unplugged the connectors, water poured out of every connector bar one :-o
> None of the connectors looked badly corroded, in fact they all looked quite new !
> I dried them off, cleaned them up, dried again, applied electrical grease to the connectors, cleaned the cover up as it was pretty dirty and refitted everything, I've taken pics so will post a how to later as it seems to be quite common
> Fingers crossed this does the job


 That's good news. As if they were wet, that could well have been the problem.
_Not good news that they should get so wet tho?_ :? 
I'd be interested to see the pics as I wonder if there is any way of sealing them up with tape perhaps.
However the grease should last a while.


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## gogs (Dec 22, 2010)

I've posted a how to Skeee, on thinking about it I sometimes hose the underneath of the car to give it a bit of a clean especially after all the salt on the roads has been dragged up, it may be that water has gotten that way I guess ! :-(


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## Skeee (Jun 9, 2009)

gogs said:


> I've posted a how to Skeee, on thinking about it I sometimes hose the underneath of the car to give it a bit of a clean especially after all the salt on the roads has been dragged up, it may be that water has gotten that way I guess ! :-(


 Good point. 
I hadn't tied the two together. My summer Lambda fault and washing. I do wash more often in summer. Especially thoroughly underneath after my many off roading exploits at Brands & Silverstone.
_It's 4wd, be rude not to. :roll: _


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## gogs (Dec 22, 2010)

Indeed Skeee, may not be related but when I unclipped the connectors and the water came out, it was the first thing that crossed my mind :-(


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## gogs (Dec 22, 2010)

Well it's come on again today :-(
I'll scan it tonight to see if its the same code, I'll get the emissions checked first as that should confirm if its the catalytic convertor or not


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## gogs (Dec 22, 2010)

Ok, scan performed one code found

16804 - Catalyst System: Bank 1: Efficiency Below Threshold

P0420 - 001 - upper Limit Exceeded

Any more suggestions? I don't want to start replacing sensors at £80 a pop if this is not the problem? Is it more likely to be the catalyst?


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## Skeee (Jun 9, 2009)

http://wiki.ross-tech.com/wiki/index.ph ... 420/001056
 16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold
Possible Causes
Leakage in Intake and/or Exhaust System
Catalyst faulty
Oxygen Sensor(s) faulty
Oxygen Sensor(s) Control faulty

Possible Solutions
Check Intake and Exhaust System for Leaks
Check Catalyst
Check Oxygen Sensor(s)
Check Oxygen Sensor(s) Control
Perform Oxygen Sensor(s) Aging Check

Special Notes
For 1.8T's experiencing this fault code, this thread may be useful: http://forums.vwvortex.com/zerothread?id=663057 

From the special notes link above:- 
Cat efficencly below threshold is usually an exhaust leak by the post O2 sensor, and it's usually at the clamp that connects the down pipe to the rest of the exhaust. If there is even a small leak, then under deacceleration there is a pressure gradient that is created. And, then the air outside is then "sucked" back in to the exhaust system for a split second.

I used to get a CEL with that code occasionally. It usually popped up at times when I was driving slowly, like in bumper-to-bumper traffic or while cruising around a crowded parking lot looking for an available space.
Also, the readiness bit for the cat would not set. I tried running the readiness test cycle with VCDS but still only the cat would fail the test.
Replacing the cat/DP with one from a low-mileage 1.8T solved the problem--readiness passed and no more CEL--and allowed my car to pass its biannual smog check easily

Mine only fails Readiness Bit 8 (last one) and stores code 16804 in summer and has only put the MIL on once in three years. So I haven't changed any thing yet. It also only fails that code when driving gently as per the extract above- so I may have a tiny exhaust leak that only leaks in summer.

*Do you have a stock DP and
have you had a good look around the exhaust for leaks?*


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## gogs (Dec 22, 2010)

Hey Skeee, only item replaced on the exhaust was the cat back Milltek, where am I looking for a leak?


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## Skeee (Jun 9, 2009)

Tbh am not certain, but if this code only appeared not long after the new exhaust then I'd start with where the new system joins the old. 
On previous cars where you have to cut and insert new mid boxes etc the exhaust fitter sometimes packs the joint with a heat setting putty/paste stuff. If used could this stuff crack and leak perhaps?

The previous VW link mentions about checking near the clamp? :?


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## gogs (Dec 22, 2010)

Scanned tonight and the code is back, no light this time though, can you still buy such a thing as an exhaust bandage? The ones that mould to the system when the car is heated up? I'm thinking if I wrap this around the join it may help seal up the join and prevent any possible leaks


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## A8VCG (May 9, 2011)

I seem to remember gungum being used for small leaks as it dries like plaster to seal in etc. Best get under there for a look and check the various joins and clamps. or just take it back to the fitter and ask him to remove and re-fit


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## gogs (Dec 22, 2010)

I'll try and have a look over the weekend Craig


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## PeTTe-N (Aug 24, 2010)

What did you do with the Oem flapper vacuum pipe when you switched to the Milltek? Did you seal it off properly?


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## gogs (Dec 22, 2010)

Just tucked it up out the way between the heat shield and valance ;-)


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## PeTTe-N (Aug 24, 2010)

gogs said:


> Just tucked it up out the way between the heat shield and valance ;-)


But did you seal off the end of the pipe?


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## gogs (Dec 22, 2010)

Nope


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## PeTTe-N (Aug 24, 2010)

Might be a long shot but could be the cause :?


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## gogs (Dec 22, 2010)

How so?


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## Skeee (Jun 9, 2009)

Where is that pipe fed from?
Just answered my own question.




V6RUL said:


> Its just vacuum from the engine that operates the flapper.
> Disconnect, plug and tuck away.
> No fault codes as there is no feedback signal to the ECU.
> Steve





Spandex said:


> Super Josh said:
> 
> 
> > Spandex said:
> ...


 viewtopic.php?f=2&t=218377&p=2051072&hilit=exhaust+mod+flapper+light#p2051072


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## PeTTe-N (Aug 24, 2010)

Just read your PM Gordon, I'm sure I read somewhere that if you leave it unblocked it can draw air into the system somewhere?? Sorry, I'm not massively technically minded when it comes this sort of stuff. When I had mine fitted I was standing watching and the mechanic said "I'll just block off the vacuum pipe before I tuck it up out of the way", I told him there was no need as I'd already blocked it for the flapper mod but never asked him why he needed too!


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## PeTTe-N (Aug 24, 2010)

Skeee said:


> V6RUL said:
> 
> 
> > Its just vacuum from the engine that operates the flapper.
> ...


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## PeTTe-N (Aug 24, 2010)

Skeee said:


> Leakage in *Intake* and/or Exhaust System
> Catalyst faulty
> Oxygen Sensor(s) faulty
> Oxygen Sensor(s) Control faulty
> ...


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## gogs (Dec 22, 2010)

Worth a shot Peter, il check this morning to see if its blocked off. I know when I did the flapper mod I had a screw wedged into the pipe but can't remember if its there or not now


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## gogs (Dec 22, 2010)

Skeee said:


> Where is that pipe fed from?
> Just answered my own question.
> 
> 
> ...


Thoughts Skeee?


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## gogs (Dec 22, 2010)

Hi Peter,

Checked the pipe this morning and it was unblocked/open, I've screwed in rather a large screw I had and am going to take it for a long blast to see if the light or fault returns


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## Marty (Jun 9, 2009)

gogs said:


> Hi Peter,
> 
> Checked the pipe this morning and it was unblocked/open, I've screwed in rather a large screw I had and am going to take it for a long blast to see if the light or fault returns


Fingers crossed for you Gordon!


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## gogs (Dec 22, 2010)

Took it for a 50 mile drive earlier, motorway, B roads and in town, no light as yet but then again it wasn't always on, so difficult to say if the screw in the pipe has solved the problem


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## Nikos3008 (Feb 12, 2012)

Sorry im no help but i get this p0420 code consistently, as soon as i clear it it comes back after 50 or so miles. I have had the sensors and cat checked but was told they are fine. So like you i am stuck with where to go next. I only get around 18mpg and im assuming it has something to do with this code, but after having it for over a year i just cant get rid of it!

Please let me know if you ever find what caused yours and will let you know too. Sorry i cant be much help but this code is an absolute nightmare to fix.

Cheers

Nikos


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## gogs (Dec 22, 2010)

Hi Nikos,

Do you have an aftermarket exhaust fitted?


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## Skeee (Jun 9, 2009)

gogs said:


> Thoughts Skeee?


 Thoughts?
At 0603!!
My only thoughts at that time were............








The point I made which got picked up straight away was _maybe _air from the Exhaust Flapper could have some way fed into the exhaust to confuse the after Cat Lambda. 
From the above comments it seems highly unlikely although there's still doubt as has been stated the end of the pipe needs to be blocked off otherwise a fault is stored. As I don't own a V6 it's hard for me to comment further on something I can't test.
All would suggest is what you've already tried, ie. to block off the pipe and see if that helps.

As you have had the exhaust system disturbed, from original I would have a good look underneath with engine running and with some sort of leak detection fluid (Soapy water? Not sure if that would work on a hot exhaust?) to be certain the new system is fully sealed.


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## V6RUL (May 28, 2009)

The reason we block the pipe is to stop vacuum generated from the inlet manifold from being wasted.
If its open to atmosphere then its the same as a boost leak.
The V6 runs in vacuum all the time and it won't be efficient with a leak.
This will also affect the MAF calculation as the engine runs on metered air.
Steve


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## Nikos3008 (Feb 12, 2012)

gogs said:


> Hi Nikos,
> 
> Do you have an aftermarket exhaust fitted?


Ive got a scorpion cat back pal but code was there before i put that on :/

This code is killing me slowly haha making me hate the car cus i just cant get rid off it its not te eml thats annoyin its the 18mpg!!!


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## gogs (Dec 22, 2010)

Thanks Skeee, pissing with rain again :-(

Steve in your opinion would this cause any issues with the fault codes I've seen?


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## gogs (Dec 22, 2010)

Nikos3008 said:


> gogs said:
> 
> 
> > Hi Nikos,
> ...


I had the code once prior to fitting the Milltek, 18mpg is low :-o I've not seen any change here, still getting around 27-30mpg

I know how you feel, I'm just fed up having the MIL light come on :-(


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## Skeee (Jun 9, 2009)

V6RUL said:


> The reason we block the pipe is to stop vacuum generated from the inlet manifold from being wasted.
> If its open to atmosphere then its the same as a boost leak.
> The V6 runs in vacuum all the time and it won't be efficient with a leak.
> This will *also affect the MAF calculation* as the engine runs on metered air. Steve


 Surely this is your issue then Gordon?

Does this mean you now won't be deserting to the Mk2 camp?
_ FWIW I had a 2L coupe FWD (Mk2) for a couple of days whilst mine was having a new MAF and N249 (big job for a dealer :lol: ) 
I was impressed by the new engine and handling was good until front end slipped going up the big Box Hill? 
But the Mk2 won't fit in my garage and doesn't look half as pretty as a Mk1._


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## V6RUL (May 28, 2009)

gogs said:


> Thanks Skeee, pissing with rain again :-(
> 
> Steve in your opinion would this cause any issues with the fault codes I've seen?


Quite possibly, but wait and see.
Steve


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## gogs (Dec 22, 2010)

Skeee said:


> V6RUL said:
> 
> 
> > The reason we block the pipe is to stop vacuum generated from the inlet manifold from being wasted.
> ...


Still undecided Skeee, if the car behaves she may well be a keeper 
The mk2 I looked at is another V6 Quattro but manual this time


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## gogs (Dec 22, 2010)

V6RUL said:


> gogs said:
> 
> 
> > Thanks Skeee, pissing with rain again :-(
> ...


Ok Steve, I'll see how she runs and take it from there


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## PeTTe-N (Aug 24, 2010)

gogs said:


> Skeee said:
> 
> 
> > V6RUL said:
> ...


Fingers crossed it works Gordon and you stick with the MK1, would be a shame to see another excellent contributor and fellow Misano Milltek V'er disappear to the dark side. :-|

But if you do, have you got a taker for your VTDA yet? :lol:


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## gogs (Dec 22, 2010)

If I do go, the VTDA will be moving over as well ;-)
I've completely demodded the car between yesterday and today, just the mk2 steering wheel to go unless I remove the clear corners as well !


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