Seat Leon MK1 1.9tdi FR - P0401 EGR - Insufficient Flow Detected

Pitchshifter

Active Member
Dec 3, 2015
10
3
From what I have read, this is a common issue. I’ve had this issue in the past and last time it happened, I removed the EGR and gave it a good clean and the code went away for a year or so.

The code reappeared a while ago and since I have removed the hose attached to the EGR to see if it’s clogged and it appears to be pretty clear.

Before I go out and spend a lot of money for a new EGR, can any one suggest any else I could try?

Below is some info on the fault:

EOBD II Error Code:
P0401

Fault Location:


Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Reduced Exhaust Gas Recirculation (EGR).
Reduced Power Output/Engine running rough.
Increased Emissions.
Possible engine hesitation.
 

bruceR

Active Member
Apr 11, 2005
2,540
616
Monifieth, Dundee
Normally one side of EGR looks Okay but the other side gets coked, I would remove and clean it to see if that is the issue then go from there.


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Pitchshifter

Active Member
Dec 3, 2015
10
3
So I replaced the EGR valve for a new one, the light went off and stayed off for my 8-10 min test drive yesterday.

I went out for a longer journey today and the light has come on again?

Will I had it off, clean the mana fold it connects to as far as I could as well as giving the exhaust feed pipe below it a good clean.
 

CupraChris1981

Active Member
Mar 24, 2021
124
12
Noob here, to save me starting a new thread does anyone have any advice on taking it off? I can only see 2 bolts but loosening them does nothing, and trying to clean without removing is probably not that effective.

I want to give mine a proper clean as it looks absolutely filthy and I am getting extremely bad mpg and power loss, this is what came up on the OBD.
 

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iammooks

Active Member
Nov 27, 2018
1,739
1,130
There are 3 bolts holding the EGR onto the manifold plus 2 bolts underneath which connects the metal flexi pipe to exhaust manifold


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And they're horrible. Don't forget that.

Put something under the EGR when you undo the bolts, because you're almost certain to drop either an allen key, one of the bolts or the gasket.

I used both a 1/4" ratchet and a normal allen key to get at the bolts. They're easy enough to get undone, but they're just very awkward to get your hand in enough to get them undone without having a really weak grip on the ratchet or allen key, hence the dropping risk. They'll go straight through the engine bay most of the time, but I have an undertray, which makes it more of a faff finding anything.


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Nam-uk

Active Member
May 11, 2011
1,111
296
lancashire.
Noob here, to save me starting a new thread does anyone have any advice on taking it off? I can only see 2 bolts but loosening them does nothing, and trying to clean without removing is probably not that effective.

I want to give mine a proper clean as it looks absolutely filthy and I am getting extremely bad mpg and power loss, this is what came up on the OBD.
that's pretty clean for a EGR when cleaning it use wynns EGR cleaner just use gloves as its strong stuff, its the other codes id be worried about and driving 1500 miles on ML light , the rail that holds the heater plugs can break up and crumble i changed mine when did the heater plugs a while back think it was 27 quid for rail at time.
 
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smutts

Active Member
Apr 12, 2020
372
188
Next time I clean my EGR, I'd not use chemicals to clean it, as the seal that stops oily crap blowing out of the vent hole had a sulk & puked oily crap all over the rocker cover ever after.

Could a lack of vacuum cause these hassles? As vacuum powers the EGR & turbo.
My car picked up 4mpg just by taping up the splits in the rigid plastic brake vacuum pipe.
The brakes also stopped scaring me now & then. Well worth 20 pence of insulating tape.
 

Nam-uk

Active Member
May 11, 2011
1,111
296
lancashire.
TPS sell the harness (or bridge as it’s called) but it’s nearer £50


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still not bad, got mine off dave (sere) and plugs but he's not there now :( nice chap him sorted me out on parts a few times, dam good prices as well.
 
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