# Failing exhaust gas sensor... or just a dodgy connector.



## horseoutside (May 29, 2013)

Found this fault recently:


```
17861 - Exhaust Gas Temp Sensor 1 (G235): Open or Short to Plus
P1453 - 32-10 -   - - Intermittent
```
Apparently the ECU uses this to measure the temperature of the gases flowing into the turbo. Normally around 300°C, higher when it's working hard, and above about 800°C I understand the ECU dumps more fuel into the mixture to try to keep things cooler in an attempt to protect the turbo. If there's no reading from this, it'll assume the worst. This will cause poor fuel economy, (duh) possibly black smoke, likely damage the catalytic converter and cause an emissions test failure. A pile of shite, in other words.

I haven't noticed poor fuel economy (~32mpg) or a lack of power, so I guess it must really be intermittent.

I cleared it, checked it again a week later, and it was back.

Either this sensor is bad or the connection is dodgy. Not keen on it being the sensor, new ones seem to be hundreds. Second hand ones can be had for €60 if you're lucky. Installation appears to be a bit of a pig, the braided hose from the sensor tip to the sensor unit runs all the way around the engine, front to back.

A bit of research told me the sensor is located under the inlet manifold, next to the dipstick:









The plastic-topped screws that secure the trim panel below the inlet manifold have had their heads stripped by a previous owner. A lot of cleaning, scraping, leaning and swearing failed to get them to move.

A bit more research told me I could undo the hex bolts securing the plate under the trim panel to the inlet manifold. Those two bolts are here:









You can undo them with an allen key or hex driver if you get it under the trim panel. Be very careful you don't drop any tools or bolts, they'll get lost in the under-engine cover and you'll be taking that off to recover them. 

With that out of the way, the sensor unbolts from under the inlet manifold with another two hex bolts. Here's the sensor, a 06A 919 529:

















Here's the connector for this sensor:









It's missing the springy securing clip on the top. The connector slides off the sensor. So, that's probably my problem... and even if it isn't, this is still shitty and needs replacing. I considered securing it to the sensor with zip ties, but the inlet manifold gets pretty hot and I think the zip ties would melt. Fire bad. So I've ordered one of these connectors (1J0973703) from a German company called Deytrade: http://www.automotive-connectors.com/1j ... icted.html

The total was €11 for 2 connectors and postage. Meh, it'll do.

I'll continue documenting the fix, and whether it actually does fix it, when it arrives. 

While I was working in there, I noticed the dipstick funnel extension was cracked and bodged together with electrical tape, my most hated of all tapes:









I've ordered a replacement on eBay for, uh, $4.45. Crazy. Cheap enough that it might be shit, but also cheap enough that it's worth trying. 

Part number: 06A103663B
eBay item: http://www.ebay.com/itm/221011652898

I didn't want to put the trim panel and mounting plate back as one unit, so I spent a long time removing (and if I'm honest, destroying) those two screws.

Here's why it was such a pig:









... and here's what I did to one of them:









So, I need a couple of these screws now, and I may as well replace the partially buggered ones on the battery cover and coolant tank cover. I know I can get a fancy stainless kit for $100 or something, but I'd rather just get a set of OEM ones. Any tips for where to order these?


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## steveupton (Mar 23, 2010)

You could try these:- viewtopic.php?f=4&t=325205

At £19 delivered, a steal.


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## horseoutside (May 29, 2013)

Yeah, that's not a bad option. Have to find a price for OEM screws first, then I'll see how I feel.


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## sussexbythesea (Apr 12, 2012)

My EGT sensor was not connected for a while, I certainly noticed poor fuel economy (low 20's on the DIS), and also the safety feature kicking in which prevents the engine getting too high into the rev range.......


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## horseoutside (May 29, 2013)

Ah, interesting, I didn't know it prevents high revs in that case. I haven't noticed that, pretty sure my fault is intermittent and that it's just the bad connector. We'll see when the new one arrives this week.


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## jamman (May 6, 2002)

One word of warning if you do need a new sensor don't go patern part or used just OEM.

ECP do them at a good price and you can use the forum discount.


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## Gone (May 5, 2009)

I have code 17861.

Is there a way to identify whether this is the sensor or the controller?

For now I've cleared it and will monitor mpg and see if it comes back. But it would be nice to know which part to buy.

ETA connector unplugged


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## horseoutside (May 29, 2013)

Gone Ape said:


> I have code 17861.
> 
> Is there a way to identify whether this is the sensor or the controller?
> 
> ...


I think the sensor and the controller are the same part, I don't think you can easily disconnect one from the other. Perhaps someone else can correct me on that...

All the 06A 919 529 parts I found online were sensor and controller together.


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## JorgeTTCQ (May 7, 2002)

Thanks for taking the time to show, very useful.


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## Gone (May 5, 2009)

horseoutside said:


> Gone Ape said:
> 
> 
> > I have code 17861.
> ...


Nonsense surely. The sensor is on the exhaust near the turbo but the controller / electronics is on the opposite side of the engine under the intake manfold. The only thing linking them as fas as I can determine is a cable, which unplugs. Not that it matters to me now anyway


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## Lucky13 (May 18, 2013)

Gone Ape said:


> horseoutside said:
> 
> 
> > Gone Ape said:
> ...


I think he did mean that they were connected by the cable and are therefore also the same part. For future reference to anyone i did min a couple of months ago as mine showed as failed. My mpg was low 20's and full acceleration multi gear runs made the car enter limo mode until you let off for a short moment. Changed the sensor myself which actually although fiddle was relatively simple and since mpg is now 30-31 and acceleration is perfect


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## horseoutside (May 29, 2013)

Gone Ape said:


> horseoutside said:
> 
> 
> > Gone Ape said:
> ...


I don't believe the sensor and the braided cable disconnects from the controller. When I had it out, they seemed pretty solidly together, the braid runs into the controller housing. Perhaps the sensor tip disconnects from the braided cable at the exhaust end, but I doubt it.

The cable from the ECU to the controller does disconnect, that's the connector I'm trying to replace. Still waiting for the package from Deytrade to arrive, I'm pretty sure it got lost in the post.


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## Wak (May 6, 2002)

Yes one part not something you can seperate!


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## JorgeTTCQ (May 7, 2002)

Hello,
Please, could somebody tell me if APX 225 engine has this sensor or only in BAM?

Thank you.


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## nickls13 (May 10, 2011)

BAM only I believe. Those symptoms sound like it's buggered. I recently had my car back to Audi for this part replacing under warranty. The MPG before was low 20's on the dis,(25 with some real maths). Since getting the car back it gone up on the DIS but not used a full tank yet for a more accurate figure. The dealers only had the car 4 days :x and from the evidence under the bonnet had left every wire for every sensor exposed from the sleeving. Still eventually got it back and now only have the, new since then, problem of intermittent low boost. Will need to check everything over.
Again.


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## Hoggy (May 8, 2002)

Hi, According to Race Diagnostics web site (Liquid TT) no EGT on these TTs... So I would think no sensor.
Definately have EGT on my 2001 BAM engine.

Audi	TT MK1	1.8T APX	1999	No EGT 
Audi	TT MK1	1.8T AUM	2004	No EGT
Audi	TT MK1	1.8T AUQ	2005	No EGT

Hoggy.


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## JorgeTTCQ (May 7, 2002)

Hi, 
Thank you very much for the answer 

Best regards


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## horseoutside (May 29, 2013)

The connectors I was waiting for finally arrived, so yesterday I fitted the new one.

The problem is the broken plastic clip on the connector for the EGT sensor:









Here are the old and new connectors:










I tried to remove the pin sockets cleanly by taking out the retaining clip (in purple below) and using a paperclip and sewing pins to disengage the sprung metal wings from the plastic casing.










After a good 20 minutes attempting to remove the pins cleanly, I gave up and carefully destroyed the old plastic connector to remove the pin sockets.


















Not proud of this, a real hatchet job. Can anyone direct me to the correct pointy tool for disengaging these clips?

Anyway, after all the pin sockets were released I just slipped them into the new connector:










Here's the new one in place. After clearing the fault code and a spirited 100km, the intermittent EGT fault hasn't reappeared.










I can see why the original clip was broken, it's really stiff. I think someone probably used a tool to pry it open and overdid it. I'm keen to find the right tool for disengaging those clips on the pin sockets - any ideas, anyone?

Thanks!


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## horseoutside (May 29, 2013)

While I was working on the EGT sensor I replaced the dipstick funnel too.

Here's the old one, what a mess:










Cleaning up the mess it left behind was pretty annoying, tough to stop any small bits of plastic falling in. I cleaned it out as best I could and fitted the new one.










For a $4.45 replacement part, it's pretty good. 

No pictures of the new one fitted, but I'm sure you can imagine. It's like the old one, except not broken and covered in crud.


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## Skeee (Jun 9, 2009)

horseoutside said:


> The connectors I was waiting for finally arrived, so yesterday I fitted the new one.
> 
> The problem is the broken plastic clip on the connector for the EGT sensor:
> 
> ...


 Do a forum search for "Molex" and, or, for "Coilpack Loom."


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## horseoutside (May 29, 2013)

Skeee said:


> Do a forum search for "Molex" and, or, for "Coilpack Loom."


Thanks!

That was the hint I needed. This appears to be the right tool: http://www.te.com/catalog/pn/en/1-1579007-6

Available from Mouser: http://ie.mouser.com/Search/ProductDeta ... bFCVPh1A==

It's a bit expensive at €56 just for a pin extractor. Perhaps I'll have another go with a paperclip, others seem to have had success with that.


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## milanonick (Sep 15, 2013)

Will be keeping an eye on this thread as I am seeing the same intermittent error being logged. Also the best we have seen MPG wise since picking the car up is circa 24.

I assume from what I have read they should be nearer 30 in normal use?


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## horseoutside (May 29, 2013)

milanonick said:


> Will be keeping an eye on this thread as I am seeing the same intermittent error being logged. Also the best we have seen MPG wise since picking the car up is circa 24.
> 
> I assume from what I have read they should be nearer 30 in normal use?


Depends if you're having any fun or not. 

I believe ~28 city, ~30 highway is normal. 24 doesn't sound healthy, I'm sorry to say.


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## Matt B (Apr 8, 2007)

Holy shit you mullered that connector. I used a paper clip opened up, both ends hammered flat and then shaped with Dremel - cost £0


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## horseoutside (May 29, 2013)

Matt B said:


> Holy shit you mullered that connector. I used a paper clip opened up, both ends hammered flat and then shaped with Dremel - cost £0


Yup. After 20 minutes fiddling with a paper clip and pins I gave up, but I'll give it another go next time I have to do something like this.


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## manikm (Feb 17, 2014)

a guy here fixes em, but its in POLISH

here is a guide....
http://elfly.pl/inne/instrukcja.pdf


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## asahartz (May 24, 2014)

My connector was like that one; I just put a self-tapping screw with the point ground off through the raised plastic section where the clip should hold. Works as a clamp to stop the plug moving, does the job a treat. Easy & cheap.


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## milanonick (Sep 15, 2013)

manikm said:


> a guy here fixes em, but its in POLISH
> 
> here is a guide....
> http://elfly.pl/inne/instrukcja.pdf


Have a look here viewtopic.php?f=2&t=454457


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