EGT sensor fault

[Ca11um43]

I don't really know when this problem started,
because it never triggers the EML and my old scanner didn't pick it up, but occasionally the fault code: 17863 pops up on my LCR. It will clear and stay off for a bit, but sometimes I randomly scan the car and it's back again.

I'm not sure if this is related, but sometimes the car feels completely gutless. For example I could be cruising in 3rd at a steady speed, then when I put my foot down I can hear the turbo but the car just doesn't go anywhere. This is very intermittent though. I could do the same thing straight after and it would boost/gain speed absolutely fine.

Most people go straight to the sensor being faulty, but I can't actually find the right one for sale (not even second hand), and from what I've read it's a very expensive part to replace, so I don't want to be spending loads of money on parts that might not fix the problem. Especially close to Christmas. I did however read a comment on the Audi forums, from somebody who owns a Cupra R, and they said their problem (same fault code) turned out to be the stock TIP collapsing. Does that sound like it could be my problem?

 

[Rich.T]

Hows the air filter looking?
Pure guess off the back of you mentioning the stock tip collapsing.

 

[Ca11um43]

Hows the air filter looking?
Pure guess off the back of you mentioning the stock tip collapsing.

It has an aftermarket ramair one on it, which I installed (brand new) a month or two ago...I do plan on upgrading to the proram filter at some point, but that's just down to personal preference really. There doesn't appear to be anything wrong with the current one from what I can tell.

An oversized TIP has been in my basket for a while now, so I guess this would be a good excuse to finally buy it. But again, I'd rather not start randomly throwing money at it, when I could put that money towards replacing whatever is actually at fault. I just don't really know how to go about diagnosing the problem. It seems to be intermittent.

 

[Alexis27]

First job is to make sure the EGT sensor is screwed in properly. It can become loose and work its way out.

If you need a new one the part is 06A919529. None on eBay, so you might need to find someone breaking an LCR or Audi TT. I bought a second hand one and it's still fine 2 years later.

The fault is usually with the solder on the circuit board in the box, so it can actually be repaired.

 

[Ca11um43]

First job is to make sure the EGT sensor is screwed in properly. It can become loose and work its way out.

If you need a new one the part is 06A919529. None on eBay, so you might need to find someone breaking an LCR or Audi TT. I bought a second hand one and it's still fine 2 years later.

The fault is usually with the solder on the circuit board in the box, so it can actually be repaired.

That's actually good to know...Will there be something visibly broken inside the box? I've done quite a bit of research in to this, and haven't seen anything about it being broken inside the box, or coming undone. I have to jack the front end up tomorrow, so I'll check both while I'm at it.

If not, I'll start looking for somebody breaking a Cupra R. I did look on ebay for either a brand new or second hand one, but like you said, there isn't anything on there at the moment.

 

[Alexis27]

It's these 5 solder joints on the circuit board inside the black box:

EGT Sensor info and easy fix (old news)

I have had a EGT code since I purchased the RS6, it was only a soft code, no CEL. 17861 - Exhaust Gas Temp Sensor 1 (G235) P1453 - 35-10 - Open or Short to Plus - Intermittent The EGT probes normally do not fail, it is the electronics in the Black (drivers bank 2) and Brown (pass bank 1)...

www.rs6.com

 

[Ca11um43]

It's these 5 solder joints on the circuit board inside the black box:

EGT Sensor info and easy fix (old news)

I have had a EGT code since I purchased the RS6, it was only a soft code, no CEL. 17861 - Exhaust Gas Temp Sensor 1 (G235) P1453 - 35-10 - Open or Short to Plus - Intermittent The EGT probes normally do not fail, it is the electronics in the Black (drivers bank 2) and Brown (pass bank 1)...

www.rs6.com

Thanks for the information...I have possibly found a few EGT sensors for sale (second hand), and they're all around the £60 mark and the sellers claim that they're working. Does that sound about right for one of these sensors? I will definitely re-solder it, and make sure it's done up tight first, though.

 

[Alexis27]

Yep, £60 sounds right. Having a faulty one killed my fuel economy

 

[Ca11um43]

Yep, £60 sounds right. Having a faulty one killed my fuel economy

I do feel like I'm going through more fuel lately...But I wasn't sure if it was related, as this fault has been popping up for a while, and I have only recently started using more fuel.

Also we have the same colour car

 

[Alexis27]

My dad had a leased red diesel 1.9 Leon back in 2001, then I got a platinum 1.6, then a black LC so I wanted a different colour for the LCR!

The onboard fuel gauge wouldn't go past 29mpg for me, even on long motorway runs. Leapt up to 34/35 when the sensor was changed.

 

[Ca11um43]

My dad had a leased red diesel 1.9 Leon back in 2001, then I got a platinum 1.6, then a black LC so I wanted a different colour for the LCR!

The onboard fuel gauge wouldn't go past 29mpg for me, even on long motorway runs. Leapt up to 34/35 when the sensor was changed.

Hmm, I went on a 2.5 hour drive (on the morway) and I think the highest it went up to on the dash was 32mpg...But this was before I found the fault. Not sure if the fault just didn't exist back then, or if my old scanner didn't pick it up. With city driving it used to be pretty steady between 26 and 28mpg if I remember correctly. Now it jumps around a lot more, between like 18 and 26mpg.

 

[mty12345]

I agree with Alexis. My vote goes to the sensor or the solder joints.

If that scanner can do live data, then get a mate to look at the EGT's (with the engine off, but ignition on) while you move the wiring. If the wiring looks ok, then the fact that it is sporadic would make me lean towards it being the solder joints rather than the sensor itself. As sensors go, EGT's are fairly simple, and don't have a huge amount to go wrong.

If the ECU sees (or thinks it sees) high EGT's, then it will cut boost straight away. I think that's much more likely to be causing the driving issues rather than the TIP colapsing, as I would imagine the TIP would collapse everytime you hit the same boost pressure.

 

[Ca11um43]

I agree with Alexis. My vote goes to the sensor or the solder joints.

If that scanner can do live data, then get a mate to look at the EGT's (with the engine off, but ignition on) while you move the wiring. If the wiring looks ok, then the fact that it is sporadic would make me lean towards it being the solder joints rather than the sensor itself. As sensors go, EGT's are fairly simple, and don't have a huge amount to go wrong.

If the ECU sees (or thinks it sees) high EGT's, then it will cut boost straight away. I think that's much more likely to be causing the driving issues rather than the TIP colapsing, as I would imagine the TIP would collapse everytime you hit the same boost pressure.

I can't actually see the wires themselves, or get to them...It's braided all the way from the plug end to the sensor, and it's tucked up behind a bunch of stuff. I can try to wiggle the wires though, with live data on. And I'll probably re-solder the box either way, as that's easy enough to do.

If not, I have found a few second hand sensors that are apparently working, so I could always just replace it.

 

[mty12345]

I can't actually see the wires themselves, or get to them...It's braided all the way from the plug end to the sensor, and it's tucked up behind a bunch of stuff. I can try to wiggle the wires though, with live data on. And I'll probably re-solder the box either way, as that's easy enough to do.

If not, I have found a few second hand sensors that are apparently working, so I could always just replace it.

Ah right, i've not got EGT on my AUQ so haven't seen the wiring. Yeah i'd give the solder joints a go first then

 

[Ca11um43]

Ah right, i've not got EGT on my AUQ so haven't seen the wiring. Yeah i'd give the solder joints a go first then

Can see the wire in the image...It's braided all the way along, and it's pretty much fixed in place on the car (doesn't move), so I wouldn't have thought that the wires would break. I guess it could still be possible though. But making sure the sensor itself is done up tight, and re-soldering the box seems like the easiest things to do, so I'll start with them and go from there.

 

[Alexis27]

Yeah the only two things that can go wrong really are the sensor becoming unscrewed at one end and the circuit board at the other.

 

[Ca11um43]

Yeah the only two things that can go wrong really are the sensor becoming unscrewed at one end and the circuit board at the other.

I do appreciate the help/information...I didn't get around to it today, but I'll definitely make sure it's done up tight and re-solder inside the box tomorrow. Will then scan the car again on my next day off, in a few days time, to see if the code has come back or not, and I'll update this post

 

[Ca11um43]

The sensor was definitely done up tight, and the solder looked fine inside the box...But I heated them up and re-soldered them any way (I couldn't add any new solder because of the jelly stuff). I went to clear the code after that was done, but it hasn't actually come back since the last time I cleared it. So I guess I'll scan it again in a few days time, and see if it has come back or not. Fingers crossed it's fixed now

 

[Alexis27]

Hopefully there was a hairline crack and you've sorted it

 

[Ca11um43]

Been a few days, and the fault is back...It took a little longer to come back this time, but it's still a problem. I guess it's time for a new (second hand) sensor