Where is Evaporative Emission Control System Purge Control Valve please? P0445

[aoakley]

Hi folks. I have a 2003 Seat Leon mk1 1.6 litre petrol 16 valve, AUS engine.

I'm getting error code P0445: Evaporative Emission Control System Purge Control Valve Circuit Shorted .

Is this the "N80" valve? Where would I find this in the engine bay, please? A photo with a nice arrow would be worth a thousand words!

Symptoms are that the car refuses to start; it turns over fine but just won't get running.

Car had this problem a few months ago; towing it and laying it up for a few days seemed to solve the problem. In the mean time I also changed the MAP sensor. Car then ran a bit lumpy but otherwise OK until now.

So it was running fine, then I filled the fuel tank this morning, then after a short drive it refused to start. Which also leads to the conclusion that this is some kind of fuel evaporation issue, so looking good for the evap purge control valve, right?

Now I think should be looking for a wiring fault somewhere near the N80 first, before I try replacing the N80... but I still need to know where the damned thing is please!

Also does this N80 thing have a fuse, if so where please? Admittedly if it's detecting a short circuit then it can't be a fuse, can it?

 

[aoakley]

BTW I know what it looks like, I just don't know where it is.

Good picture of this thing: (not enough posts yet to link)

c1552172.cdn.cloudfiles.rackspacecloud.com/5226_x600.jpg

 

[mty12345]

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Here you go mate, where the arrow is, the N80 is what the connector plugs into, if the 1.6 litre is a different layout, the cannister and valve should look identical.

 

[aoakley]

Brilliant, cheers Matty.

I take it that the bucket-like thing that it is stuck into, is the activated charcoal filter?

Should I need to remove & replace the N80, how hard is that job? Is there a risk of breaking anything if I try?

(I can rebuild a PC, I can change a wheel, I can clean an EGR valve, I can replace an ECU but I am no mechanic - I'm a computer programmer in my day job. Just one with a family who needs to avoid big garage bills.)

 

[mty12345]

No probs, you're welcome mate. You're exactly right, the bucket thing is your charcoal canister and if you need to replace the N80 it simply prises out of the canister with a flat bladed screwdriver, almost no risk of breaking anything really.
I highly recommend getting a copy of this http://www.ebay.co.uk/itm/VW-Audi-S...2014-CD-DVD-/121766237177?hash=item1c59d553f9

It contains loads of info for working on all models of our cars and you can do pretty much any job within reason then. It can be a PITA to install sometimes, but if you're a computer programmer then i would imagine it will be easy for you.

SEE BELOW THOUGH AS I DON'T THINK THE N80 IS YOUR PROBLEM!!!

 

[mty12345]

Sorry I was busy trying to do a few things at once when i first saw your post and only half read it mate........I've seen that code come up when the fuel pump relay has failed...... I think that may well be your problem as the N80 as far as i am aware shouldn't affect the car starting, but the fuel pump relay definitely will

 

[mty12345]

Fuse 28 is for the fuel pump, so it could be that, but as i said i think it's the relay itself. There is a guide here to get to the relay, it's behind the lower facia on the drivers side http://www.icecavern.com/howtos/leonlowerdashtrim/main.php
It will be the relay with 409 written on it, far right hand side. (Use the long part number on the side to order a new one)

One last thing is be careful that you don't accidently touch those terminals under the relay panel, as said in the guide they are on a 110amp fuse! You can obviously disconnect the battery first, but then you need the radio code and the engine will run rough at first until the ECU re-learns the fuel trims, i'd leave it connected and just be a bit careful but it's upto you.

 

[aoakley]

Cheers for the continuing advice.

Car sat in my office car park overnight, and guess what, it started first attempt this morning.

Combined with the fact that I filled it up with fresh petrol yesterday, only two hours before it refused to start, and that the last time it failed to start I'd also recently filled up, plus the P0445 OBD code specifically stating the evap valve short circuit, I'm still thinking that this is an evaporative emissions control problem.

My theory is that leaving it overnight gave the fuel vapours time to evaporate off of their own accord, hence why it started this morning and not yesterday.

Nice theory - now I need to get my hands dirty, check & change the valve and find out for real. It might take me a while to get the spare time to do this, but hopefully I'll report back - if I forget and someone in the future wants to know how it pans out, PM me to remind me to update this thread.

 

[mty12345]

Yeah that's possible i guess mate, but the tank has an emergency vent which should vent to atmosphere if the pressure gets too high. The N80 is there for enviromental reasons really, as venting fuel vapours to the air kills polar bears apparently
Hopefully it will be ok, but if you have more problems after changing the N80 then i still think fuel pump relay is probably the culprit. They have a tendency for the contacts to stick in the open position, especially if they are warm/hot at the time. Once they cool down then the contacts can free up again. AFAIK the relay also controls the N80 and energises it at the same time as the fuel pump is switched on, so that could be the reason for the N80 short circuit code.

Either way if you can report back when you've got the time please mate, as it help people in future if they have a similar problem. There's nothing worse than finding a thread with the same probalem as your car, only to find there was never any conclusion Cheers.

 

[aoakley]

Right-o, will also check the fuel pump relay. That's got to be a cheap and simple job so it'd be silly not to do that while I'm at it. Or even first, before ;-)

Note to self: disconnect battery before messing with relays, as my understanding is that the only fuse between my fingers and the battery will be 110amps... these are high ampages that can kill quite happily, zapity-zap-zap.

Thanks again for the help.

 

[leegreenaway]

I removed mine altogether just have it venting down into the wing and a resistor in the plug!

 

[aoakley]

This is now fixed.

In short, Matty was right. Replacing the fuel pump relay fixed the problem once and for all.

I did replace the evap valve first, before I replaced with fuel pump relay. This improved things, especially initially, but after 3 weeks the non-starting problem came back and after a further couple of weeks got worse and worse again.

There was no sign of damage or scarring on the old fuel pump relay, however I disposed of it and replaced it with a brand new one from GSF when they had one of their discount weekends.

Result was instant. Car now starts up the very moment I turn the key and after a month of having the new fuel pump relay, the fix is consistent and there is no sign of the non-starting problem.

It's interesting to note that the fuel pump relay has a gazillion contacts. Clearly it is doing a lot more than just turning the fuel pump on and off.

Changing the relay is a very simple job that can be done with a screwdriver and a spanner - and you only need the spanner to disconnect the battery. Once the battery is disconnected, remove the fuse panel cover from the side of the dashboard near the driver's door, then there's some screws, then there's a couple more screws under the dashboard. Prise the lower dashboard off with firm but careful force, then disconnect the headlight switches by removing the plug. Hey presto, you have access to the relay panel. The fuel pump relay has the number 409 written on it and it simply pulls out.

The thead "How to - Change Brake Light Switch" has a nice photo guide to removing the lower dash, including which screws need to be removed. (not enough posts yet for me to post URLs, sorry)

 

[aoakley]

Another interesting point to note, is that before I replaced the fuel pump relay, the problem could be worked around by removing the evap valve (easy to do, you just wiggle it a bit and pull it out - it has a little O-ring which makes an airtight seal, watch out in case that pings off), waiting 2 mins or so, then pushing it back in. This requires no tools and you can easily do it by the side of the road. The car would then start. So clearly there was something about the evap valve not properly moving the evap fumes to where they should be. However since the evap valve is *controlled* by the fuel pump relay, it would have been better for me to have replaced the fuel pump relay earlier. However with this trick you CAN get a drivable car if you need a few days/weeks to afford or take delivery of a new fuel pump relay.