Passat 1.6 TDI p0407

[Roverfan]

That is a strange symptom that it only happens on startup, not sure what it points to though. What oil/additives do you have in the system? Something gummy may slow the response of the egr down when cold but its a long shot. Also it could be something electrical which is also effected by temperature or startup demand, or is loose..

[philipharmes]

The EGR does a self test at ignition on & also off I believe, so if any part is snagging, the self test over it's complete operation range could be bringing up the fault.

As Crasher has pointed out many times, these aftermarket EGR's basically aren't fit for purpose, genuine VW ones aren't much better.

You could temporarily fit one of these to see if the problem is eliminated.
EGR Valve Simulator / Repair 1.6 TDI - VW Audi Seat Skoda - CAYA CAYB CAYC CAYD | eBay

I've only used the Tafmet one which is a bit more expensive, but totally effective, if it eliminates the fault you will know where the problem lies.

[Patters1978]

Cheers for the replies guys

So I haven't spent much time trying to fix the car over the last few days lucky I have 2 cars!

Anyway tonight i thought I'd give the MAF a clean to see if that helps and when I tried to start the car it didn't start at all just turning over!
Stop and started again and just turning over until I hear something fall from under the car!!
I took the key out straight away and retrieved a clip that had come off.
Decided to try and start it again and it finally started with the same issues as before! Bummer

Now dunno if the car is just falling apart now or I might have got lucky in trying to pinpoint the issue with this clip flying off?
The part number on the clip is
3C0 711 637

I have googled and it's a heat shield clip but from the diagrams I have no clue where this is from or if it might be connected to anything that might cause this issue,. But whatever it's close too sure took a beating when it wouldn't start as it really hit the ground hard?

Any idea?

[Crasher]

It is just a cable guide heat shield clip.

[Patters1978]

It is just a cable guide heat shield clip.

Where does it come from bud?

[Crasher]

I think it is for the pre cat lambda sensor.

[Patters1978]

Another weekend going over this thing,. I'm running out of options now so garage soon.

So today I have tried to swap over the electric motor part of the EGR so I could try the one from the original but first I thought I'd try to see the plastic motor spin while it was off the EGR.
Nothing happen even when the engine is started doesn't move at all, tried the old one again nothing?
The vacuum unit works fine.
Now ever since removing the electrical connector to the motor I have a constant glow plug light illuminated.
It now has the old "VW" motor in which hasn't fixed the issue, I have taken the battery off the car just to see if it will remove the fault as my trusty crap reader can't erase the error now?

What I'm thinking is I have a dodgy wire, me messing about with it might have now just broken it completely.
I find it odd the electric motor don't spin at all? Is that normal
Any idea what type of voltage I should see and on what pins? And diagrams?

Cheers

[Crasher]

You can test the EGR unit with VCDS in output tests and check it’s functionality in Basic Settings, without VCDS your are fighting a loosing battle.

[Patters1978]

You can test the EGR unit with VCDS in output tests and check it’s functionality in Basic Settings, without VCDS your are fighting a loosing battle.

I'm thinking of buying it tbh £225 tho
I have also found an article showing voltages at the plug so I will test that also, would have thought that motor would of spun.

Out of interest is there a fuse I should check?

[Crasher]

It is directly driven by the ECU