ECU repair advice

pandsnolan

Member
1.6fsi 109k

Hi following my post last friday the A2 has been in the garage and been tested , although for me it shows all the head gasket symptoms , runs cold and then dies when warmed up , and I am pretty sure there was at least one spot of water by the expansion tank. Anyway the guy in the garage after lots of testing thinks it is the CCU .
I asked about getting an ebay spare, there are a couple on for about £80. He advises that you cant fit a spare and it needs to go away to be repaired as it has all of the code for the car on it ? I asked about repair cost which he advised £25 courier, £75 test charge which you get back if you proceed with repair, and £££ hundreds (ouch, ouch ) for the repair .

Any advice on can you swap units ? or most economical repair very gratefully received.

Many thanks
 
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A2cars and Timmus both do an exchange service for the CCCU. As A2cars is considerably closer to you than Tom I'd recommend you give them a call. You'll save hundreds on dealer costs. I don't think you can buy the eBay item and swap it yourself. It needs coding to your keys etc
 
I believe you are possibly referring to the ECU? The CCCU deals with on board functions where as the ECU manages your engine.

As Mordo has stated get in touch with these 2 and I would almost guarantee they could fix it! If they don't know you may as well give up!

Perhaps if you post a few more symptoms and description of the fault it may help? The FSI has a complex thermostat that is controlled by the ECU unlike a lot of cars where the thermostat is a non managed item. Do you have any fault codes off the ECU? I would hope the FSI would report on such faults as it could just be a sensor somewhere or poor earth etc,
 
I agree the post must refer to the engine ECU (tried to modify the title accordingly but failed) and can only assume the garage think the ECU is not sending the correct signals to the electronic thermostat.

Installing a second hand ECU has it's own problems as it must be programmed so it 'talks' to the engine immobiliser. This may be beyond the scope of the guys at your local garage.

Agree with the other suggestions so if it's practical, book it in to A2 Cars at Milton Keynes

Cheers Spike
 
Title modified and disregard my post about CCCU although these guys are probably still the people to talk to as Paul says.
 
Hello,

I believe this is the original thread... http://www.a2oc.net/forum/showthread.php?29361
The fault codes retrieved by the garage in their investigation of the car's problems can be found by following the link. For the sake of continuity, it's often best not to start new threads relating to the same issue.

As has been said already, the problems described here are related to the engine's ECU and not the central convenience control unit (CCCU).

As Spike says above, swapping engine management units isn't a simple process due to complications with the immobiliser. Whilst myself and a select few others here are able to do so, I can't imagine there are many 'any-make-any-model' garages in the country who can do it. If the existing unit was sent away for repair, chances are it could simply be plugged in again and there would be no immobiliser issues to overcome. However, I'm sceptical about the garage's diagnosis. The FSI is a troublesome engine; owners who haven't had issues count themselves fortunate. Despite its many foibles and the long list of possible cures, I'm yet to read/hear about a problematic FSI that's been fixed by replacing/repairing the engine management unit. Furthermore - whilst I don't wish to be overly critical of a garage unfamiliar to me - it sounds like a spurious diagnosis borne from confusion and lack of any other ideas. All too often, with modern cars governed by electronics, non-specialist garages blame expensive parts like injectors and control modules when they're flummoxed. There's a first time for everything and I'll happily be proved wrong, but I'd be reluctant to spend any money on sending an engine management unit away for repair when I had no firm evidence that it's broken.

If the engine management unit is a firm suspect, I'd first be swapping it for one that's known to work. There are plenty of FSIs being broken for spares these days, so the necessary part is easily picked up. Whilst it does require software to get it to shake hands with the rest of the car, it's a means of ruling out that possible cause of problems without spending hundreds of pounds.

Is the car mobile at all, or is it effectively stranded with the aforementioned garage? If it can be moved, I'd recommend you get it to WOM Automotive. Whilst outwardly VAG specialists, their real expertise lie with the A2. They've put a lot of time and effort into understanding the FSI in particular and have rebuilt a number of FSI engines from scratch. Furthermore, they possess the necessary software to be able to transplant engine management units. Although a professional garage, they're long-time A2OC members who'll do a proper diagnosis rather than just playing 'parts darts' and charging you for the privilege.

http://womautomotive.co.uk/contact-us/

One way or another, I hope you get the issue resolved and breath new life into your A2. :)

Cheers,

Tom
 
Just swapping the ECU is a 10min job as long as your old one is working, with programing.
And it's not really true that you need to re-program it ;) You can just remove the immobilizer chip from the old ECU and re-place the IMC on the new ECU (done it a few times where the ECU has been burned out).

And there are also ways to easily de-activate the immobilizer.
 
I echo Tom's comments.
It would be extremely rare for the ECU to be the cause of these issues.

I have never seen anyone on here who has had to replace or repair one and that is over many years and thousands of posts.

You need a garage that knows the A2 well.

These days even Audi's own mechanics are mostly unfamiliar with the A2 (the last time a dealer sold a new A2 was over 10 years ago)

Wasting money on a replacement ECU or a repair to it is far from ideal.

Steve B
 
Hi thanks for your advice .

When it broke down the problem is that wont run when it gets up to temperature and stalls , chugs away for a second or two like it is only firing on one or two cylinders, and dies. Runs OK when it is cold though .
I have always had a bit of a missfire ever since I have had the A2 , again this only shows itself when it got upto temperature , I had been working through the ideas on the forum to try to fix this .... eg coil packs , earth point, fuel system cleaner .


I have real nagging doubts about it being the ECU too and already had it in my mind that it was the head gasket . Pete at the garage said hooked it up and monitored the stream and said that the temperature reading went from normal down to a really low value -30 and the engine died but tried to run on after it had stalled . The fault codes that show are 17796 and 17428 dont seem to be an obvious link to the symptoms .

Spikes reply looks pretty much like the conclusion that Pete at the garage has come up with and put it down to a faulty ECU . Any more help really appreciated.
Many thanks
 
Hi thanks for your advice .

When it broke down the problem is that wont run when it gets up to temperature and stalls , chugs away for a second or two like it is only firing on one or two cylinders, and dies. Runs OK when it is cold though .
I have always had a bit of a missfire ever since I have had the A2 , again this only shows itself when it got upto temperature , I had been working through the ideas on the forum to try to fix this .... eg coil packs , earth point, fuel system cleaner .


I have real nagging doubts about it being the ECU too and already had it in my mind that it was the head gasket . Pete at the garage said hooked it up and monitored the stream and said that the temperature reading went from normal down to a really low value -30 and the engine died but tried to run on after it had stalled . The fault codes that show are 17796 and 17428 dont seem to be an obvious link to the symptoms .

Spikes reply looks pretty much like the conclusion that Pete at the garage has come up with and put it down to a faulty ECU . Any more help really appreciated.
Many thanks
 
Hi thanks for your advice .

When it broke down the problem is that wont run when it gets up to temperature and stalls , chugs away for a second or two like it is only firing on one or two cylinders, and dies. Runs OK when it is cold though .
I have always had a bit of a missfire ever since I have had the A2 , again this only shows itself when it got upto temperature , I had been working through the ideas on the forum to try to fix this .... eg coil packs , earth point, fuel system cleaner .


I have real nagging doubts about it being the ECU too and already had it in my mind that it was the head gasket . Pete at the garage said hooked it up and monitored the stream and said that the temperature reading went from normal down to a really low value -30 and the engine died but tried to run on after it had stalled . The fault codes that show are 17796 and 17428 dont seem to be an obvious link to the symptoms .

Spikes reply looks pretty much like the conclusion that Pete at the garage has come up with and put it down to a faulty ECU . Any more help really appreciated.
Many thanks


A head gasket will only cause the engine not to run when the temperature gest so hot that it is throwing steam out of the system.

The leak from the gasket does not affect the running much at all, after all it is just sending a tiny portion of exhaust gasses into the coolant / oil system.

So these symptoms are not those of a failing head gasket (unless you are getting steam at the same time is stops running?)

Steve B
 
Steve

Thanks again for the support , as you said the ECUs seem pretty bombproof, I hope someone has experience of the thermostat function . Pete from the garage has pinned the problem it on this sudden loss of correct temperature measurement function , affecting all of the other engine functions ...... he is not an A2 expert though .
From looking through the posts 1.6 fsi seems to have good few difficult to diagnose issues.
 
This info on fsi thermostats illustrates just how complex the unit is - http://www.a2oc.net/forum/showthread.php?19248-thermostat&highlight=1.6fsi+sender+thermostat

Cheers Spike

Meant to add that the comment above about logging cooling temps and seeing a reading of -30 suggests major issues with the calibration of one of the temp sender units.
The engine ECU uses this info to optimise fuelling and ignition timing etc so the mismatch between this reading and actual coolant temps may be the cause of the poor running.
It would also explain why the electronic thermostat appears to be closed even though the engine is hot.
 
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Id message A2steve as sure he can help you out with the parts to just replace it all ,
youl need a drivers side door lock, ignition barrel and ecu and the key, not the fob thow as youl need yours as paired to your cccu , sure he had the parts last time we spoke so u may be in luck , and its just plug and play and you could easily do yourself with just a few tools and basic skills , it will take about an hour to swap everything over and would also be alot cheaper to fix this way.
 
17796 is a drive by wire monitoring issue, suspect this may be an issue but not causing the complete failure when warm.

http://wiki.ross-tech.com/wiki/index.php/17796/P1388/005000

As for 17428

Look here for options

http://www.bba-reman.com/forums/Topic90762.aspx

And one off the forum that suggests fuel pump / system could be an issue

http://www.a2oc.net/forum/showthread.php?12147-Problems-With-My-A2

The fsi is a complicated beast, fantastic engine when all is well and this is from a tdi lover! You would be far better placed finding a guru as they can get it to health far more efficiently than most. I genuinely feel you are sadly experiencing a few issues but not all will be attributing to your stalling issues. For me look at the fuel system first.

I reckon the drive by wire is a random glitch and would discount this for now.

Good luck!
 
Hi

Thanks all for your fantastic help . From reading through all the posts here , the places to start look like the thermostat assembly ( which I assume houses the temp senders too?) and the high pressure fuel pump , although I cant get my head round the fuel pump as the car runs OK when cold, but also having read through is controlled from the thermostat too , so all seems to lead back there?.

Any wisdom would be appreciated ?

I will run through with Pete at the garage and hope that he can get his head round the thermostat opetation
 
Hi been in touch with the garage and have some new information .
Latest info / thoughts from Pete :
When the car reaches the correct warmed up temperature the SHORT TERM FUEL TRIM goes haywire and the IGNITION TIMING jumps to MINUS 23 ° ie 23 degrees AFTER TDC which is why the engine has no power. These two are the critical points and indicate an ECU fault. The fault code 17796 / P1388 indicates a Control Module Fault (to do with the DBW monitoring ) A fault with the DBW actuation such as a throttle pedal circuit fault would give a different code. The throttle position sensor voltage is given by the datastream also and isn’t a problem.
The other recorded fault code was 17428 / P1020 Fuel Pressure regulation Control range exceeded. This is more uncertain as the pressure sensor may be at fault or the High pressure fuel pump or of course the wiring. However after clearing the code and running the engine twice until it died the fault code has not returned. This makes me think it unlikely to be the main cause of power loss. Also probably a fault in this circuit would probably put the car into Limp Home mode so it would still drive albeit slowly. It wouldn’t account for the ignition timing going to After TDC.

He is going to talk to the ECU repairers and try to get advice from there experience . The likely causes of the symptoms above are so varied that this beyond me even guessing . Any experience /suggested checks to perform welcomed , the tie in with the temperature is the one that really baffles me if I am honest .

Thanks once again, fingers crossed there is some past experience out there .
 
That sounds just like the car entering "limp mode" rather than that being the actual cause of the problem.


The engine deliberately reduces power significantly when it detects a significant problem.

Unfortunatley we are well past my electrickery know how, I just didn't want the settings to be misred and cause extra expense if it is just "limp mode" caused by another problem.

Steve B
 
Steve

No the car wont run when it gets temp arround 96 degC . Just suddenly chugs a bit and dies , runs fine upto this point .
 
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