P2556 code, please help if you can

[chrisbutnosurname]

Hi all, sorry for the long post, but please help if you can.

My car is an A5 2.0 TFSI 2014 quattro 225

Code I get is P2556 - Engine coolant level sensor/switch circuit.

• Car runs ok
• Coolant level ok
• Temperature gauge seems to not operate, but under faster driving goes upto ~60 degrees.
• Heater not functioning well, dribbles warm air on hi/auto, upon manual operation, goes cold.  I have noticed that the heater works quite well if I use the windscreen clear button, heat comes through much better.
• air con works
• radiator fan is constantly running

VW/Audi specialist failed to diagnose and repair, they have serviced the car and carried out the following repairs to try and fix this issue, none of which have sorted it:

• temperature sensor valve replaced
• coolant bottle replaced
• Auto electrician, 4 hours but not repaired, everything is okay right now from a wiring perspective.

The specialist said take the car to a main dealer for diagnosis which was a little frustrating. During the repairs, on a day I had the car back in between, another dash warning appeared, looked like a temp guage in water, red in colour and stated to stop the car and check the coolant level, which was ok. After auto leccy work, warning has stopped but the P2556 remains and symptoms the same.

Specialist told me car is ok to drive.

A friend of mine suggested might be a radiator sensor problem, based on a similar fault on a merc, but not sure about that.

If you have any ideas, I would appreciate the help.
 

[Magnet]

Hello Chris,

Sorry to hear of your issues. 

Of course, it's always difficult to diagnose problems at a distance, particular when specialists, who have had access to the car have failed. 

Let's try to deal with these one by one:- 

Coolant level sensor- you don't say if this sensor has been replaced, unless it was when the reservoir was renewed. This could be as simple as a dodgy connector onto the actual sensor (normally lives inhospitably, under the reservoir). If it were mine, I would be removing the connctor and treating it with contact cleaner and reconnecting/disconnecting it a couple of times. Not cured? Change the sensor for a VAG one only ( aftermarket ones can be more troublesome). 

Coolant failing to reach temperature - surely the 'specialists' can carry out actual live temperature readings as this car as it's being driven. This will confirm or refute if the gauge reading is correct or not. If the actual coolant temperature reaches to around the upper 90s then suspect the renewed temperature sensor (VAG or aftermarket?). If the temperature only reaches around 60 - which I suspect it will- then suspect the thermostat. 

Why would the thermostat have failed on a 2014 car?? Actually been removed to mask overheating?? You might, just might find that someone has been 'in there' before, and the renewed thermostat has failed. 

Perhaps you could let us know how you get on Chris.

Kind regards,

Gareth.

[chrisbutnosurname]

Gareth,

Thanks for your reply, I'll try to expand on your questions.

During the diagnosis, the specialist changed what I believe to be the temperature sensor with a genuine part, this failed to solve the issue, but I'm not sure if he put the original back on and sent the new part back or not, but I can check. 

He then changed the coolant bottle, again with a genuine part, apparently there was some evidence of a leak as the plug at the base of the bottle was showing some discolouration to the copper contacts, this was cleaned up.  I did notice a low coolant level prior to taking the car for service but topped up with distilled water just to get the level up before I took for service, I asked if this could be the signs of a leak, but as the level did not change at all in the time between my topping it up and the service (which was a couple of weeks) they thought it wasn't an issue, especially as the discolouration of the contacts was minor.

Apparently they have checked the coolant temperature and the car doesn't get above 65 degrees.

They then had an auto electrician spend apparently 4 hours checking the wiring, he stated that the wiring was not faulty, but that a repair had been carried out previously in one area, but it seemed to be a good repair to dealer standards, not really sure what that was.

To be fair to the garage, they have not charged me for any of the work that didn't solve the issue. but I think they don't want to keep doing work they cannot charge me for, which I can't really blame them for.  That being said, they have had £380 for the service so it's not altogether free.

We did discuss the thermostat, whilst discussing the water pump housing (a possible issue which I had seen on the net somewhere), but apparently, to replace it is a 4 hour job with a quite expensive part (circa £500 all in), I'm not opposed to having that done, but I have to admit I don't really want to have that done if its not the answer, but that's the price of owning a second hand car I suppose.  This is the job the garage doesn't want to do in case that doesn't fix the issue, so maybe I need to bite the bullet and just get it done.

I will indeed keep you posted with hope this issue unfolds.

By the way, I've not had much luck with this one, the turbo needed replacing, but luckily that did surface the day after I picked it up, took me 6 months to get the dealer to fix that though.

Hope you have a great new year.

Chris.

[Magnet]

Hello Chris,

Many thanks for the additional useful information. 

Low coolant level warning? Now seems inexplicable with knowledge of what has been done. I think I would still suspect this to be associated with a contact issue, and I would revisit this if it were mine, but if you keep an eye on the actual level then I guess this spurious warning would be something that can be lived with. 

Temperature only getting to 65 degrees? 

I would put my money on this being a thermostat issue, despite the car being only 4 years old. Not sure where it lives in your engine, but   4 hours labour would suggest it's somewhere inhospitable! A total estimated cost of c£500 would equate to the part costing only c£100 ( labour est. at £100/hr). If it were mine, I would be wandering into (another) Audi dealer and getting an actual cost and description for the part, and establishing whether the part is available as simply the thermostat, or if it is supplied including a housing (usually plastic). I would then be enquiring about the cost of fitting it at the same main dealer. It would also be useful to have an alternative quote from an independent.

I've just replaced the thermostat on our 12 year old 1.6 A3 and that is now spot on on temperature, as opposed to being reluctant to get close to 'normal'. If you do decide to replace yours then my recommendation would be to only fit a genuine VAG part (particularly with the anticipated labour charges) since aftermarket ones can be variable in quality and reliability - so just don't go there!  

Does the car have a full main dealer service history? When did you buy it, and did you buy it from a main dealer. Subject to the answers, it might be well worth contacting Audi and presenting your issues to them - they may be prepared to make some contribution. 

I hope 2019 is kind to you and yours, and that you can get this issue sorted easier and cheaper than the current estimate.

Kind regards,

Gareth.

 

[chrisbutnosurname]

Thanks Gareth, some good info there.

It's a bit of a long story, I bought the car from a national company that has many dealerships, the one I bought from was not Audi.  At the time there were not many models like mine on the market, some were much more expensive, some cheaper, I thought I had picked the right one for me, particularly as it could be moved to my location, but unfortunately it didn't work out that well, I think I have been sold a car that had problems that the dealer knew about and hid well, the ones I could prove were eventually sorted, but only after I flexed my brain and found out what my rights are, basically I threatened to take the car back for a full refund, even after six months, which I found was my right based on what they had done (not repairing the car in a timely manner), but my mistake was trusting them and allowing them to repair what I knew at the time was wrong.

Anyway, pointless crying over spilt milk, it is what it is and I have learnt a lot.  I have to admit, I am torn between trying to fix the issue and enjoying the car and just getting rid via webuyanycar and leasing something new, but I can't really afford a new audi on lease and I love the A5 (minus the faults).  Just worried I might be repairing a sick car for ages.

The car does have a main dealer service history, apart form the one I have just had, which was at an Audi specialist, they did update the Audi service database, but I have a feeling that Audi may not make any contribution due to not using their network for the recent service.  Not too bothered about that if the problem can be sorted, just don't want to pay for repairs that don't exist, but I think you're probably right about the thermostat and might be the best option.

So apparently the thermostat is under the manifold on my model, so 4 hours labour was quoted, the specialist isnt as expensive as a main dealer on hourly rate so I think thats where the estimate of £500 came from, was only a stab at a price by the way.

One thing I did find out for those of you struggling with other car issues after buying form a dealer, if you have issues with a car, you have 30 days from the date of purchase in which you can return the car and request a full refund for any reason, got that from citizens advice.

Thanks again, I'll keep you posted.

Cheers.

Chris.

[NottsDam]

Hi Chris, I’ve exactly the same car and exactly same issue. Did you sort it in the end? If so what was the cause?

[chrisbutnosurname]

Hi Damion, I'm sorry to say I never fixed the problem or got to the bottom of it, the signs pointed towards thermostat but the chance of replacing that only to find I'd be chasing a problem with the main dealer draining my bank account put me off, so I cut my losses, sold the car back to the national dealership that rhymes with heavens gal shore and have now leased a vw arteon which I have to say is a great car, not as much fun as the audi but a lot cheaper to run and full of toys. 

None of this answers your question so sorry I can't help more, good luck, there is a service audi offer, which includes funding all or part of a repair if your car is out of warranty, presuming it is as you're on here, but it felt like I'd have to go crawling to the dealer as its their decision if to offer and how much, might be worth a try tho. 

[NottsDam]

Thanks  Chris,

I've tried a few things myself already. Going to change the fan sensor tomorrow since it's pretty cheap and easy to get to. Have already changed the temp sensor in the block and disconnected and cleaned the contacts for the coolant bottle. Also did a full coolant flush and change the other week. Suppose next step might be a thermostat change but not sure how easy / difficult that is on this engine. I watched a vid on youtube of a guy doing an S5 and it looked a right pain. I don't trust the code i'm getting either so might have it properly scanned. Typical as i was just about to sell the car too! If i do ever suss it out i'll let you know what it was. 

All the best

Damion

[chrisbutnosurname]

Hi Again,

Sounds like you have tried everything the garage I originally took mine too, they actually changed the coolant bottle and back again when that didn't fix it, that was a VW/Audi specialist and it stumped them, well to be honest, they didn't want to do any more work on my car without charging me, which I couldn't really blame them for as they had spent a few hours changing parts without charge, it was then they asked me to get it diagnosed at an Audi dealership and bring it back once I knew what it was, that was when I got a little suspicious that I might end up chasing cost, the specialist did suggest the next thing would be a thermostat, but they told me on my model it is under the manifold so would be around 4 to 5 hours work, I think I was looking at around £700 for that job and no guarantee it would fix it, all in all its what lead to my decision, it cost me around £3k of lost car value, but there we are.

Stupid question, but I presume you have a code reader and have cleared the code only to find it return?

I suppose you may need to try to get an Audi dealer to diagnose as they apparently have a larger database of issues, but you're possibly looking at a couple of hundred quid just for the fault finding.  Alternatively its one of the car purchase companies, I took mine back to the dealer I bought it from and they gave me a better price than webuyanycar by around £400 but did reduce the offer by £700 when I told them the fault code.

By the way, during my issue, the cruise control also stopped working, I wasn't sure if this was related, a symptom of a poorly car that would clear if I fixed the fault, but it never started working again when I cleared the code so I was concerned that would be another cost, I read that cruise is a common fault and costs £250 to fix, so that was another nail in the coffin.

If you chase the fault, I truly hope you find it and fix it quick, I never expected this from an Audi, it's one of the reasons I bought one in the first place, but you live and learn I suppose, give the dealership some grief and quote this forum to show there are similar issues elsewhere, I'd be happy to rant along with you if you need that.

Cheers.

Chris

[chrisbutnosurname]

This is another stupid idea, but how long have you had the car, is it red, was the registration number BL63CSF, just checking you didn't buy my old A5 from the same dealer, as crazy as that might be, if you did, you could probably get the repair funded as you would have bought the car with a pre-existing fault and I'd be more than happy to return the favour they did to me by selling me a knacker (this is just wishful thinking on my part).

Anyway, like I said, bonkers idea but stranger things have happened.

Chris.

[NottsDam]

Hi Chris,

Yes i do have a scanner but it's only a £70 jobby. I changed the coolant temp on the rad hose last weekend but still got a dodgy temp gauge on dash. I scanned just before i changed and i've still got the P2556 + had the P0116 <which relates to temp gauge issue, come back. I've cleared these fault codes several times yet the P2556 comes straight back as a pending fault and then within a few starts and stops of the ignition it lights up the MIL again. The scanner can display live data and the ECT degC was reading 70ish while the dash went up to 90 while sat on the driveway. As soon as i drove it though the dash temp dropped to 70 and the scanner to 65 so defo something weird going off on that front.  I also cleaned the contacts again for the coolant bottle Re: the 2556 code but as you say its probably nothing to do with that at all. Reading around on the net the only two remaining options seem to be a thermostat Re: the dodgy temp gauge although i still can't get my head around that one or some kind of electrical fault / bad earth. I'm not really any good with electrics although i do have a multi meter. I was able to check the resistance change on the old temp gauge by running under hot and cold water. I did get a change in resistance so seemed that might have been working fine. Spent about £50 on new sensors so far so not too bad really. 

No mines White but is a 63 plate so not the same car. Interesting though that it's exactly the same fault and same model and there are a host of other people on various forums and different models of Audi that report them same issue - I've just not yet found a single person who found a fix as of yet. I've had the car 5 years and bought from an independent garage in Peterborough so no chance of getting much assistance off Audi.  

So this weekend I'm hoping to take it to an Audi specialist garage for a proper VAG scan (Not dealership as they've already charged me £160 for a scan while it was in for a service) although to be fair the temp gauge issue wasn't happening then (i don't think - conspiracy theorists eat your heart out) and the fault code i had has since gone after i changed a coolant actuator - something they'd highlighted. they wanted £700 to do that and it cost me £30 :)

I'll see what this garage recons and take it from there. Hoping they also help me figure out where the thermostat is and i may change that myself. Looking at the parts on web it looks like it could be accessible from the side of the block but i'm not 100% on that yet. There seems to be about 4 different versions that come up even when i use my reg to identify the car?

I'm a bit of a stubborn git when it comes to problems like this so i'm still determined to get to the cause - i just can't afford to fork out a small fortune as i'm currently saving like mad for a new kitchen which I've already had to put back 3 months - living in building site is no fun! I'll keep you posted.....

PS: If anyone is reading this in the Nottingham area and has a proper scanner or is a dab hand at auto electrics please get in touch - i'll sort you some beer / cash...

 

 

[chrisbutnosurname]

haha you sound like me, I also live in a bit of a half finished house, bought a fixerupper a while back then realised i'm not a fixerupper kinda guy, I need a builtforlazygits house, but the missus isnt for moving now.

You also sound much more adept at fixing your car on the driveway, much more confident than I am, I'm the sort who thinks its good when I put something back together and have some spares left over for next time.

The only other thing that was a little different for me was the temp gauge on the car mostly read between zero and fifty degrees (more towards the zero), but the garage told me it was running fine and the temp was spot on, they even said leave it and everything will be fine as it's running perfectly, but I couldn't live with a warning light on all the time and no temp warning.

As for speaking to Audi, there is the theory that he who shouts loudest gets attention, think about when a 5 year old keep saying "can I have, can I have" eventually we give up and give them what they want just to shut them up.

A 6 year old German engineered high quality vehicle should perform much better than they do so some guilt trip might work if you get the right person on the other end of the phone, then again it's easy for me to say as I gave up and went to sulk in the corner of the garage.

Its a sad fact that German engineering isn't quite as good as they make out, but the same can be said for all German cars I suppose, a lot of guys in my office complain about post warranty BM's and Mercs too.

Good luck with the fight.

Chris.

[NottsDam]

Thanks Chris,

I spoke to the so called Audi specialist today who was frankly useless. As soon as i mentioned that the fan was running on full whack he assumed that this was causing the temp issue and started waffling about the fan control module -frankly he seemed as baffled by it as me. 

I did some more investigation tonight though. I plugged in my scanner after a 7 mile drive, same faults as usual. I then started the car but just ran the engine without moving and the dash temp climbed to 90 deg, the live data on the scanner (ECT temp) only climbed to 74. Fan didn't come on whilst i did this. I tunred engine off to see what would happen. Sat watching both readings for nearly half hour and barely any change in either. ECT dropped to about 71deg. I then started the car for about 5 seconds and the ECT dropped by 7 deg within seconds but dash temp barely moved. Waited again for another 10 minutes and repeated. this time ECT dropped to about 65 and dash temp to about the same? 

I'm really trying to figure out if it's a thermostat issue or an electrical issue? Can't find anything online at all ref this and this site hasn't been much help either as it feels like there's only me and you on it!

Still trying to figure out where the thermostat is, seems there's 2, one regular type and another one which is really slender, think it's part of the water pump? So i'm now faced with either getting an auto electrician out of having a go at the thermo but don't know which one to replace. think the reason i can't find anything for this particular model is as you say - 5 year old audi's aren't expected to have such issues....... really tainted my view of Audi!

[chrisbutnosurname]

Yeah it all tainted my view of Audi too.

Each time you post something else it reminds me of other things that were checked, the specialist I went to apparently had an auto electrician all over the wiring, he didn't find any faults but he did find that some electrical work had been done before and I think that was on or around the water bottle, something to do with the colours of the wires, if i remember correctly, he suggested the wiring had been repaired as there were some yellow wires where they should have been white or something like that, this apparently signifies that changes have been made, I think that's designed in to enable an easy spot if any work has been done, or so he told me anyway.  he did claim that the work had been done well and suggested it had been carried out by a main dealer, which would sound about right as i bought mine just after the warranty had run out.

This all feels like a story for Holmes and Watson, it's becoming that deep an investigation, you would hope Audi are watching these forums and would offer some help, but that would be like admitting they have a poor design or inadequate parts used, come on Audi, man up and take responsibility for your actions!

Have you checked the service history with Audi yet, there is a number you can ring direct to Audi which can give you the run down of your cars history including any work carried out under warranty, I think it largely depends on who you get on the phone, some aren't quite as helpful as others, for instance the first person i got basically spilled everything to me, but when I called back about something else, the next wouldn't break at all and said i would need to contact a dealer to get info, so it's probably about how you sweet talk them.  If you get a good one, they should be able to help at least with the cars background and if that shows there has been work done before similar to whats happening now,there might be a claim, I'm stretching a little, but anything is worth a try.

Here are some contact details i found:

How do I contact Audi UK?

Audi (UK) complaints contacts

1. Visit Customer Services.
2. Email Andrew Doyle (Director of Audi UK) on andrew.doyle@audi.co.uk.
3. Call Customer Services on 0800 699 888.
4. Email Customer Services on customer.services@audi.co.uk.
5. Tweet Audi (UK) Customer Services.
6. Tweet Audi (UK)

I'd try the Andrew Doyle one, but it probably doesn't actually get to him.  Have fun.

[NottsDam]

Hi Chris, Brief update.

I'd bought a replacement thermostat but still wasn't 100% sure where it goes. The pictures on the sites that sell them show an arrow pointing to the collant actuator / water pump housing. I'd asked the supplier via email where its located on the car and they replied saying they weren't allowed to tell me - wtf?

Out of curiosity i'd asked a local garage how much to replace the thermostat and they wanted £750 with no guarantee it would fix the issue. I was all set to remove the entire water pump and coolant actuator but in the end i thought i should probably get a second opinion. So yesterday i took it to another 'Audi specialist', in Nottingham. They called me back to say its the coolant reservoir.  I was surprised and asked could that really cause the temp to read funny, they believed it could. £70 replace and fit + £50 diagnostic I thought my luck was in. But at the back of my mind i remembered that you had also tried this approach so i wasn't overly excited. Just picked the car up, drove about 2 miles, called into a shop and when i jumped back in the engine management light back on. Car didn't reach temp driving home and scan reveals the P2556 coolant low level fault is still there. 

They've asked me to take it back in tomorrow. I can only assume that they didn't actually do any kind of diagnostic into the cause but simply plugged into scanner and believed what it was telling them - so much for being a 'specialist'!

[NottsDam]

SOLVED!!

Was the thermostat in the end, which some reffer to as coolant actuator. Latter is probably more accurate since it's an electronic motor driven device which performs the same function as a thermostat. 

It looks as though the thermostat housing had failed, and not at the classic location of where the unit attaches to the block either, but somewhere right in the middle. The garage has let me keep the defective part so i'll be ken to investigate the cause more closely. Not just ouf of curiosity but also to provide feedback to audi themselves. A £300 pound part, in my view should not fail on a 6 year old car. Especially when any typical thermostat would cost less than £40 and probably be easily fitted by the owner and certainly not a multiple hour job for garage like this was. 

I also believe that it's this leak which must have cause some kind of oxidation of the coolant which then also cause a secondary water pump motor to go - which shut off the stop/start function, and the level sensor in the coolant reservoir. All in all a very expensive, time consuming and frustrating few months. 

I'll post some pictures up soon of the faulty part. Be interesting to see what anyone else thinks  

[bonchev]

 

On 9/6/2019 at 7:26 PM, NottsDam said:

SOLVED!!

Was the thermostat in the end, which some reffer to as coolant actuator. Latter is probably more accurate since it's an electronic motor driven device which performs the same function as a thermostat. 

It looks as though the thermostat housing had failed, and not at the classic location of where the unit attaches to the block either, but somewhere right in the middle. The garage has let me keep the defective part so i'll be ken to investigate the cause more closely. Not just ouf of curiosity but also to provide feedback to Audi themselves. A £300 pound part, in my view should not fail on a 6 year old car. Especially when any typical thermostat would cost less than £40 and probably be easily fitted by the owner and certainly not a multiple hour job for garage like this was. 

I also believe that it's this leak which must have cause some kind of oxidation of the coolant which then also cause a secondary water pump motor to go - which shut off the stop/start function, and the level sensor in the coolant reservoir. All in all a very expensive, time consuming and frustrating few months. 

I'll post some pictures up soon of the faulty part. Be interesting to see what anyone else thinks  

Hello,

Did you change only the thermostat or the whole engine temperature control actuator n493