Jump to content
feeblington

6n2 p0420 p0401 p0106

Recommended Posts

feeblington

Hello again.

Yet more lemony goodness from my pile of bolts

I have the errors mentioned i have an aua engined 6n2 and have checked my 02 sensord and map and they are working. Soneone suggested to check the vacuum hoses and clean out the egr. Can anyone point me where to start. No idea where the vacuum hoses are and how to remove the egr. Is there a knack or an order to removing?

Any help or suggestions would be awesome as im at my wits end. Oh and the ecm light came on too 

Share this post


Link to post
Share on other sites
feeblington

Thank you. I seem to have trouble finding anything!

Cheers again 🙂

ive so far  sorted the 420 as was just wiring plug loose. As for egr ive got it off and its gunky as hell so im gunna clean all the pipes and it. Hopefully wont need to replace.

Now. The map/thrust sensor.

how do i get to this on an aua engine?

i think i can just about spot it hidden near the dipstick. I just havnt anything to go on.

cheers again again :D

 

Share this post


Link to post
Share on other sites
nige8021

The MAP/IAT is on the end of the inlet manifold (by dipstick) held in with two torx screws, when you remove it be careful to not drop the "O" ring, clean it with a spray carb cleaner don't use a brush or anything similar as they are quite delicate 

Share this post


Link to post
Share on other sites
feeblington

Sweet. Can i get to the map sensor without removing the dipstick and surrounding pipes? It looks well tight

 

Little update. Had the egr valve cleaned and pipes cleaned...still came up with error 401 after 6miles. Deffo need a new one haha.

 

Share this post


Link to post
Share on other sites
nige8021

You can get at the sensor without removing anything but it is a bit tight on space, especially if you have JCB shovels for hands but a 1/4" ratchet and the torx bit it is do-able 

 

Before you condemn the EGR valve, take the main engine disconnect connectors apart (by the thermostat housing) and give the pins/sockets a spray with contact cleaner (not WD40)

Share this post


Link to post
Share on other sites
feeblington

Ill give the cables a spray.. is it the group of plugs near the dis? 

Share this post


Link to post
Share on other sites
feeblington

And again thanks ill try find my 1/4 rachet 😯 

Share this post


Link to post
Share on other sites
nige8021
1 hour ago, feeblington said:

Ill give the cables a spray.. is it the group of plugs near the dis? 

 

They are down by the thermostat housing near the battery tray

Share this post


Link to post
Share on other sites
feeblington

So the cables are pretty immaculate. Haha

And another update. Pulled egr off again and tried moving the valve. Seems jammed midway. 

Also i managed to get my hand in by the map and pulled plug out. Gave spray of contact cleaner.

Ive done around 200miles since that and only error is 401. Fingers crossed thats all it was. Car has also not had a "hiccup" or whatever its called.

However seems a bit low on power. Almost like the last 1/3 of pedal motion makes no difference. This has been gradually becoming more noticable for last month or so. And after a quick google points to egr or 02 sensor (which btw had an error about 1.5k ago for high voltage on post 02 sensor but error has never returned).

You reckon the lack of power is or could be egr related.?

Cheers

Share this post


Link to post
Share on other sites
feeblington

More update . After another clean the p0401 hasnt come back.

However p0138 is now appearing. 30second after i turn engine on. Every time.

Im aware this is post 02 sensor high voltage.

Any ideas where to start looking for problems. Also where is this 02 sensor located?

Cheers again

Share this post


Link to post
Share on other sites
vwfan3
1 hour ago, feeblington said:

More update . After another clean the p0401 hasnt come back.

Cheers again

After the clean, did the EGR valve still jamm midway, or did it move full way.

Share this post


Link to post
Share on other sites
feeblington

No i have a fairly crap code reader. 

401 is back and no it didnt move full way. So im going to replace that soon as i get round to it.

As for post cat sensor. Ill have a look this weekend when i get some time. Cheers again ill update soon 🙂

Share this post


Link to post
Share on other sites
feeblington

So i had a look underneath and coulsnt spot anything obvious. Are the post cat 02 sensors easy to replace?...is it likely to be the sensor? Or is this a case of fault finding 😞

Share this post


Link to post
Share on other sites
nige8021

As you have already checked the pins/sockets on the disconnect down by the thermostat housing, as that is a common area for corrosion on the pins, then that only leaves the sensor itself,  it is reasonably easy to replace but before you do, soak the joint in plus-gas (not WD40) a couple of times then make sure the spanner is a good fit or you can buy a special 1/2" drive socket with the side cutout to allow the cable passed, then it's a case of unclipping the wiring back to the connector and refitting the new one, you can put some ant-sieze compound on the sensor threads, just make sure none gets onto the sensor head itself. 

Share this post


Link to post
Share on other sites
feeblington

Hmm. I had the map sensor error come back earlier. Havnt had any sign while driving other than the light  deleted code and cleaned plug and its gone again. As for the post cat 02 sensor i soft wire brushed the outside and sprayed some contact cleaner and that errors also gone. 

I havnt had time to sort egr yet but have the part. I cant jack my car up tho so im parking on wonky curbs atm 😕 and its making access to the sensor awkward to say the least. Im gunna get a new sensor and try and get it into a garage so i can have  good look at the wiring underneath.

Without your help guys i dno how id be doin this.

So again thanks 🙂 ill update when i have something to update

Edited by feeblington

Share this post


Link to post
Share on other sites
feeblington

Hey all.

So i replaced the egr. Cleaned out pipe to TB and had light cleared. P0401 came back.

Ive also got an 02 sensor for post cqt but after getting under the car...mine seems to have a lead half a meter long....but looks like it needs to be over a meter...any ideas whats happened here? Has the previous owner bypassed the connector to make it awkward ha!?

But what else could the p0401  be?

Ive been through google and haynes manual more times than i can count.

Help!

Share this post


Link to post
Share on other sites
nige8021

I wonder if the little filter #17 https://volkswagen.7zap.com/en/rdw/polo+derby+vento-ind/po/2001-240/1/133-133011/#17  could be partially blocked not allowing enough vacuum pressure to fully open the valve so giving the EGR Low flow detected ?

 

From memory on my Ibiza the wiring from the post cat lambda run up to the bulkhead then across by the steering rack then forward to the disconnect, so yeah the lead would need to be a few feet long, but it's quite possible atsome time in it's life someone couldn't be bothered to unclip the full length of the wiring and just cut and spliced it ??  https://volkswagen.7zap.com/en/rdw/polo+derby+vento-ind/po/2001-240/9/971-971018/#61 this is where it should connect too, down at the front of the engine

Share this post


Link to post
Share on other sites
feeblington

That filter...should it be connected to anything? 

Had a 2nd look at 02. Deffo spliced. Makes me wonder why the one i ordered has such a short lead

 

Ill clean filter tomorrow . Also is it worthing cleaning where egr mounts to manifold?

Share this post


Link to post
Share on other sites
nige8021

The filter should be to atmosphere 

 

Was the lambda a genuine Bosch one a that should have the full lead, but there is nothing wrong with splicing it.

 

It might be worth giving it a clean, nothing to loose. 

Share this post


Link to post
Share on other sites
feeblington

Nah its ridex. Im a poor ass. Only few parts carry bosch with me (mainly filters lol)

I tried blowong through the vacuum hose. Seema blocked. Put a pin through the end but i dunno what im doing here. Ill pull 02 off and clean when i get some nice weather. 

Cheers nige

Share this post


Link to post
Share on other sites
nige8021

Been looking and unless you get the 030 906 262 C  it's the "C" that denotes a 1.6M lead without the C you get the short lead designed for the earlier models that only had a pre-cat sensor in the downpipe so only needed a short connection lead, I did find this https://www.ebay.co.uk/itm/Intermotor-Oxygen-Lambda-Sensor-64254-Replaces-030906262C-030906262F-XLOS1197/323550649215?epid=1334724620&hash=item4b551f1b7f:g:8ZsAAOSwkvtb7OC3  not a Bosch but it has the full length 1.6m lead 

 

You could try just removing that filter and see if you can blow through the pipe from the valve end ? 

 

The hole in the mainfold should be good and clear, and though the adapter #35 in the previous diagram

Share this post


Link to post
Share on other sites
feeblington

Ok the little air filter is free flowing. Im gunna take egr off tomorrow morning and clean manifold side. Ill splice the rear 02 sensor aswell. Fed up with this bloody thing!

Still p0401 after abother clean out. Do i have to get the ecu reset or recalibrated. 

Also whether this has any effect. Car seems low on power. Feels more like an 8v than a 16v at the moment . Someone said possible air leak? Im not sure where to start. Pipea going to the TB look in good nick. Only pipe thats abit fudged is oil breather to crankcase. Which sends a fair amount of oil up...also spotted a slight oil leak from sump gasket. Any of these related or have i just got more issues?

 

Share this post


Link to post
Share on other sites
nige8021

On one car I had a look at the owner had been using a generic code reader to clear the faults but they kept returning, but when I put the VCDS on it and cleared the codes they didn't return, I'm not saying this is your problem as in theory once the code has been cleared it should only return if the fault still exists.

 

Air leaks are not unheard of, closely inspect all the pipes coming from the throttle body/inlet manifold, 

AUDVacummpipes.thumb.JPG.004be08f1abd4541d288741ec0a4ae27.JPG

 

These are the sort of things to look for, also there is a big thick tube from the manifold that goes to the brake servo and they have been known to crack

 

If the breather system isn't working as it should then it migh be increasing the pressure in the sump causing the leak 

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. Terms of Use Privacy Policy Guidelines