EGR Valve short to earth problem - and soloution

Rorybtc

Member
Hello everyone. I have recently joined the Audi A2 fleet and have been restoring a 52 plate Audi A2 1.4 16v basic model back to its former glory.
This has involved:
Replacement gearbox
Replacement clutch
Replacement Power Steering Pump
Replacement Battery
Replacement Front and rear brake pads and shoes
Replacement Steering rack boot
Replacement Cambelts, water pump etc kit including auxiliary belt (Had original factory one....)
Replacement Plugs & HT Leads (These were from the factory too!!!! HT leads were almost sold!!!)
Full service (Engine flush, Ignition system flush, all filters, new engine and gearbox oil etc)
New service flap retention clip
The most extreme interior and exterior clean (the previous owner had been using it to transport logs and fire wood, after their children had spilled all manner of sticky sweets/drinks/chewing gum etc over almost every interior surface of the car....)
AND.... a replacement EGR valve.....
So, the reason I thought I'd put up this post was to save my fellow A2 owners from the grief I endured sorting out this problem.
I had the ECP and engine management lights on the dashboard, and the computer was reading code for the throttle body and EGR valve (throttle body code was because the EGR valve was faulty). The original EGR valve on the car was in one piece, but the upper body with the connector would easily swivel 'that's not right' I thought. Also the duff EGR valve was causing all sorts of running problems, as the ECU and therefore the throttle was trying to compensate for it not working (over revving when changing gear being the most irritating and uneven idling). And when hooked up to the computer it was coming back with the EGR SHORT TO EARTH error code. So a new EGR valve was ordered.
Replacing the EGR valve was a relatively easy procedure - especially if you remove the studs fixing it in place from the head (loosen the two nuts, then put another one on each stud, tighten them together using two spanners and - with a bit of luck - remove both studs) this saves having to remove the feed pie to the throttle body. To fit the new EGR valve, reverse the procedure. The old EGR had electrically failed, rather than being bunged up with gunk, so the feed pipe didn't need cleaning out.
So, new EGR all fitted, hooked it up to the computer to clear the codes.... and the same fault EGR SHORT TO EARTH code kept coming up. So, my brother and I (he's an excellent professional mechanic - both my brothers are actually) set about trying to find the fault. I checked on the forum, found advice on checking the loom for friction/rub points, we checked all of those... inspected the loom wherever we could get access to it, tested it for signal. Frankly looked everywhere but couldn't find the short!!! Somehow, voltage was not reaching the EGR.... So we had dinner, I did some more research and then I found the PDF on the forum listing all the various systems covered by the fuses. Low and behold, FUSE 31 amongst many other things is for the EGR valve. So, back up to the workshop and I whipped it out - BINGO!!!! one popped fuse. Put a new one in and my life was changed!!!!!!!!!!! I've driven the car over a thousand miles in the last week (long story, I had to get the car on the road in rather an unexpected rush) and had slowly been falling out of love with it. Over revving between gears, bogging down when pulling away and drinking fuel like a very thirsty, thirsty thing - it was 'a nightmare'. Obviously as you'll appreciate I'd poured a lot of money and time into this car, and I was starting to think I'd made a dreadful mistake....
But, the car is transformed. For a 1.4 16v it goes like a rocket, is almost silent on tick over and I'm sure its going to run on air from now on.....
So the moral of this story is.... ITS FUSE 31!!!!!!!!!!!!!!!!!!!!!! Don't forget to check your fuses if your getting the EGR SHORT TO GROUND code!!!!! It might save you an awful lot of grief. ;) Rory
Audi A2 Oct 2022.jpg
 
Short to earth usually means the component is not receiving power. As you eventually found it was not receiving power due to the supply fuse for that circuit being blown. Hindsight is a wonderful thing but always start with the power source and see at what point the power is no longer being supplied. Another thing is do not just look at any fuse you need to test it with a meter.

I suspect in your case the EGR had shorted out due to the loose half and this had blown the fuse.

Impressive list you have of the work done and am glad you can now enjoy the car. The way to look at it is every time the car makes you smile knock a few quid off the cost of the repairs and you will soon be back in "profit".

Nice tip on removing the studs for the EGR valve. I doubt many would have thought of that.
 
Superb!

We have all been tripped up by a fuse myself included it cost me about 6 hours and a saw head, in that case some plonka had been messing with all the fuses, now that's where I always start on a unknown vehicle with fuse inspection and testing, a mega cheap test light is superb for testing fuses (unless they are the sealed top type grrrr!)
 
Fantastic, good find & thanks for putting it here.

Glad you found the problem, I had a fuse issue not so long ago & once replaced all problems went hopefully for ever, the car now drives lovely.
 
I have a lot of the same symptoms.

1. EGR Vacuum Regulator Solenoid Valve Short-circuit to ground.
2. Cruise/Brake Switch (A) Circ. Malfunction.
3. Fuse 31 blown.

I tried to replace the blown 10A fuse, and erase the fault codes. But the error codes came back.

Tomorrow I will replace the EGR valve with an original Pierburg one. (I'm excited to see if I can do it, without having to loosen the transfer tube. I don't have a new gasket on that end.) And I'm replacing, just in case, the Brake switch as well.

I'm hoping that the error codes will go away with a new fuse after all this.

But I've seen posts where similar errors come from a heating element in the crankcase ventilation system. Hope I don't have to replace it too.
 
I can confirm that it is the crankcase ventilation heating element that was the source of the error messages for me as well.

I replaced the brake light switch, and replaced fuse 31. The error messages came back, and the fuse blew.

Then I disconnected the connector on the heating element on the crankcase ventilation, replaced the fuse, and deleted the error messages.

Voila! The car has no error messages and warning lights. Now I just need to find a replacement part and plug it back in before winter comes...
 
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Your wish is my command! :D It is placed on the right back side of the motor compartment, on the rubber ventilation tube going up from the oil separator further down.. I have reconnected it, and wrapped the connector cable in plastic to keep the dirt away. You can see the plastic wrapped connector pinned between two pipes not far from the heater pipe.

Does anyone know there to get a replacement Genuine Heater Pipe ( Part # 036906391A) for a nice price?

(I am going to give the old girl a good motor wash one of theese days! I Promise!)


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Hi @Troender, did you manage to get a replacement heater pipe? and if so, where from?

I just replaced the cambelt on my 1.4 and noticed the connector to the heater pipe was disconnected, so reconnected it, and guess what? The fuse blew and I got the EML and EGR short to earth code.

I have disconnected it again - does anyone know what issues I might get if I leave it disconnected?

Cheers
Pete
 
It's time for an update to this thread.

As I said furter up in this thread I finally found out that it was the heating pipe in the crankcase ventilation hose that caused fuse 31 to blow. Finding a new part was difficult, but after installing a used heat pipe and resetting the error message, the problem went away.

It lasted for a few months until I was on my way back from a completed Mandatory roadworthiness test.
It was -25 degrees celcius outside, and the code returned. Same error as last time, but with a different heating pipe.

There is something causing the error to reappear. Could it be that a new oil separator free of gunk will solve the problem?

This YouTube Video points in that direction. (Secound half)

 
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