Hi everyone, new member here. I’ve just purchased a 1 owner 2001 1.0 6n2 60k on clock, every receipt imaginable to go with it, even original pre registration receipt from September 2001. Bought as a “kind of” non-runner. The car itself is driveable (as I drove it 35 miles home) but the previous owner said it hesitated badly on acceleration, badly being and understatement - however not expecting it to be rapid, it’s a 1 litre after all. Plugged it in to a diagnostic and it came back with fault codes P0401 & P0408 (EGR fault codes). I’ve changed the EGR valve but fault P0408 (EGR Sensor B circuit high) still remains. The car itself pulls well in first gear but then there is nothing in any other gears, literally struggle to get up to 60mph. Also noticed that the car won’t rev over 3500/4000 rpm, thought the car could be in limp mode due to lack of power but no codes are coming up for that (not sure if limp mode would throw a code up?). Really hope someone out there can advise on this, be a shame to see a rust free example with this much history attached broken up into parts. Thanks in advance Andy.

I have no experience on a 6N2 but I have removed EGR valves, fault codes on other cars.  Apologies if some of what I say is a bit generic.

 

Many codes will cause limp mode, and your rev limiting and low power does sound like limp.  I suspect that when the P0408 is solved the limp mode will clear and you will have a working car.  You might need to manually clear the codes with the diagnostics machine - have you tried this already and did they come back by themselves?

 

From what I can see from googling your EGR valve unit

https://www.onlinecarparts.co.uk/car-brands/spare-parts-vw/polo-6n2/14172/10651/egr-valve-intake-manifold.html#10104

(engine code AUC, 999cc, for year 2001 - is this your car and EGR?) has a vacuum spur on the side and an electrical connector on the top.  Either of these could cause fault codes if there's a problem.  You've fitted a new unit so it's unlikely (but not impossible) this is defective out of the box, so I would check the connecting components, electrical and vacuum.

 

i) Bad electricals.  Bad connection or earth in the cable that clips to the EGR. Firstly just check that the connectors look clean and that it clips on snugly, there's no obvious damage to the wires etc. If you can get a circuit diagram for your car you will be able to find what wire in the connector does what.  You can then check the supply voltage and earth is being supplied correctly and determine if there's a problem further down in the circuit.  I always try to find a diagram and identify terminals before multimeter testing, as its possible (especially in resistance mode) to damage an ECU by incorrect multimeter use, although neither I nor any of my friends have ever experienced this in real life.

 

ii) Bad vacuum.  Check your hose is not split or obstructed, and that it is connected well at both ends.

 

Its also worth checking the exhaust feed to the EGR, was it gummed up with muck?  Was the old valve dirty and jammed when you removed it?

 

Hi there Bread, many thanks for replying to my post, that is the correct car, my new EGR valve has part number 030131503B. I have tried to clear the fault codes manually but the code P0408 will not clear. I’ve not opened the old EGR valve to see what’s inside and I’ve yet to get under the bonnet and have a good look around since changing the EGR valve due to work commitments, however this weekend I will have a full day at it on Sunday, where I will for sure go through your check list with a fine toothed comb. I have ordered a Haynes manual for the car and that should be here by Friday so hoping there is a wiring diagram in there to help me. Really appreciate your reply on this. Hopefully get it running properly, then it will be a £275 bargain lol !.

 

That's from the dealer manual as I don't think the Haynes will cover this, The Valve is N18 G212 is the position sensor and if you see there is a box with 25 in it that is the 5v sensor supply from pin 62 of the ECU and another box with 35 is the sensor earth that goes back to pin 54 on the ECU

Hi Nige8021. Many thanks for the diagram, straight over my head to be fair but I’ve got a good friend who is decent with electrics so hopefully you have pointed him in the right direction and I’m a step closer to a normal driving experience. Thanks again.

All of the wiring for the valve goes through a 14 pin connector down by the thermostat housing and they are prone to corrosion on the pins/sockets normally affecting the Lambda sensor wiring 

 

On the valve connector you're looking for +12v on pin 1 via fuse 30, a 5v supply on pin 2 and a ground on pin 4 

Brilliant, thanks very much for this info, it’s much appreciated 👍🏻.

Hi all.

 

A quick update on the above. I believe I may have potentially fixed the problem, the front CAT was blocked !. Car now runs fine, gutsy (for a 1.0 🤣) right the way through the whole rev range, however fault code P0408 still remains. Further investigation required over the weekend.

 

Andy 

https://www.obd-codes.com/p0408  &  http://wiki.ross-tech.com/wiki/index.php/16792/P0408/001032

Hi Nige. The wiring is going to be my first port of call at the weekend 👍🏻. All vacuum pipes are fine. Cheers for the info / wiring diagram once again. 
 

Regards

 

Andy

 

 

Hi all. Though I best update this thread in case any members experience the issues I had. Turns out that the Maniverter and front CAT were fine, clean as a whistle. The problem lied with the centre pipe and rear silencer, both blocked up which was causing the lack of power. Now changed and the car is much more happier. Thanks to everyone @clubpolo for all their info, diagrams etc etc. 

 

Andy