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 Post subject: Re: ECU repair
PostPosted: Sat Sep 17, 2016 11:42 pm 
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Nibbles wrote:
I'm happy to do it for the cost of postage. I suggest using special delivery as this is tracked & insured, bearing in mind how rare these are. Usually about £20 each way. Drop me a PM if you want.


Thank you, I very much appreciate the offer. My nephew is going to have a look for me, he works for Cambridge Audio building stuff and so is quite nifty with a soldering iron and pcb's. If he feels nervous I will take you up on your offer thank you :D but am quite hopeful that with the earlier discussions and pictures in this thread he'll be happy and confident to undertake it.

Any links on where to get the components? I scanned the lexus thread that JP had posted a link too, and it made me nervous of what to order. Sam had suggested he could probably get them from work but now I'm feeling like being a little more cautious.

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 Post subject: Re: ECU repair
PostPosted: Sun Sep 18, 2016 7:54 am 
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I've got a couple of spare 10uf 50v Panasonic fc if you want them (pm me your address).

These 2 caps seem to be the only ones that fail, the other caps seem to last fine. (I'm tempted to change mine soon anyway though just incase).

Otherwise it's a look at rs components Farnell or suchlike for electrolytic snap-in capacitors of the above value and 105 deg c ratings. I am far from experienced in this stuff but in the hi-fi world the Panasonic fc are commonly recommended as a reliable good quality brand/type so I stuck with it for the ecu (I doubt the low esr has any effect here ;-)

The solvent cleaner and hpa for cleaning and sealing the pcb were around £25 delivered so not too expensive either and just do a search on eBay for the fans of stuff Chris shows in his images.

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 Post subject: Re: ECU repair
PostPosted: Sun Sep 18, 2016 8:05 am 
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Actually you can buy all of the bits off Amazon if you don't mind using a company that has interesting uk tax affairs

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 Post subject: Re: ECU repair
PostPosted: Sun Sep 18, 2016 8:31 am 
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As above i have loads though i don't think they're Panasonic, they are good brand 105 degree though.

For cleaning i use fluxclene which comes with a stiff brush, though you can use any suitable solvent e.g. white spirit, thinkers, isopropol

For spraying afterwards confirmed coating e.g. hpa is ideal as it contains moisture repellent, fungicides etc. You can also use any laquer e.g. wheel laquer, but it won't be so good in very damp conditions.

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 Post subject: Re: ECU repair
PostPosted: Sun Sep 18, 2016 8:35 am 
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Ps. I will highlight again that just swapping capacitors is unlikely to cure the problem. There is normally track damage you will need to put wire links across. I'm happy to talk him through it if needed.

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 Post subject: Re: ECU repair
PostPosted: Sun Sep 18, 2016 10:55 am 
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Thanks fellas, I appreciate the help :)

I'll get the bits ordered and give you a shout if we need anything, I'm actually a sparks by trade and he does design and build PCB's as part of his job so hopefully the checking of continuity and bridging any damaged areas should be fine, it;s the process of touching something very hot to a virtually irreplaceable ECU that got me really nervous.

I'll let you know progress as and when.

Interestingly enough, whilst trawling round looking for info, it appears that this is a problem beginning to plague Vauxhalls too, saw a couple of companies who where selling exchange units for a variety of them.

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 Post subject: Re: ECU repair
PostPosted: Sun Sep 18, 2016 7:18 pm 
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Once the problem is known & understood, repair is about 1/2 hour plus a few pence in parts for someone who knows what they're doing. Your Nephew should be fine, if he does some design he should understand the principles involved.

To do the job commercially, there is a large 'liability' element which could cost a shed load of money if something goes wrong. This would require charging a fair chunk of money to make the risk worthwhile. This is partly why I do a 'capacitor change' free as a favour with no guarantees it will cure the problem.

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 Post subject: Re: ECU repair
PostPosted: Mon Jul 17, 2017 9:46 pm 
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I bought a gt4 CS last week as a non runner. The previous owner had someone look at the car and they supected it was a ECU/electrical issue but could not find the fault. Being from a electrical backround i decided to take a chance on the car and trailered her home.
My Saturday was spent following electrical diagrams and fault finding to no avail so i started to suspect the ECU. Saturday evening i came across this thread after being told about it from a member on here,after reading this thread and others i was having very similar symtoms with my car,no start,no ECL at all.
When i removed and opened up my ECU lo and behold i found the two 10uf capacitors had leaked and i was getting no continuity from the positive terminal on the capacitor on the top board to the rest of the board(the triangle part).
I had no suitable capacitors at hand so i just bridged out the damaged track with cable, plugged the ECU back in and she fired straight up,delighted. Have capacitors ordered so will replace them when they arrive. Big thanks to the members who created these threads and im looking forward to becoming familiar with the forum and its members.


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 Post subject: Re: ECU repair
PostPosted: Tue Jul 18, 2017 7:46 am 
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Pleased you found and sorted it Darbre :)

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 Post subject: Re: ECU repair
PostPosted: Tue Jul 18, 2017 5:46 pm 
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jeff wrote:
Pleased you found and sorted it Darbre :)

Thanks again Jeff for pointing me in the right direction.


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 Post subject: Re: ECU repair
PostPosted: Tue Jul 18, 2017 6:28 pm 
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Great to see that the extensive experience available on this forum has been of use :)

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 Post subject: Re: ECU repair
PostPosted: Wed Jul 19, 2017 9:33 am 
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It's great that cars are being saved with a fairly simple fix that would otherwise be unviable with these ECU's being so rare. The cost of an aftermarket ECU plus mapping and associated loss of safeties and limp modes would send many of these cars to the scrapheap.

I am now starting to see reports of the same fault on other celicas, including the equally rare convertibles which again have a specific ECU.

Interesting it's been confirmed the ECU runs without the capacitors fitted, this largely confirms my thoughts that they are 'decoupling capacitors', and the lack of a ceramic capacitor in paralell is probably the reason they are failing. Maybe I should consider using a 10uF surface mount ceramic instead as a replacement.

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 Post subject: Re: ECU repair
PostPosted: Sun Jul 01, 2018 11:29 pm 
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I think it's worth another update and bump to the top as ECU's are now falling like flies on all models of celica gen 5 & 6 and also equivalent MR2's. Also heard rumours of supras and lexi but I'm not on those forums.

It's certainly not limited to CS/RC or gen 5. I suspect these appeared first as the ECU's are much rarer and can't just be picked up from a local breaker..

From the range of car types and ages I very, very, very much doubt it's a 'bad batch' issue unless a buyer made a mistake and bought a million packs not a million capacitors and they spent the next 10 years using them up !!!!!!

Knowing these capacitors are across the 12V supply and therefore appear to be bulk decoupling. I would say the most likely theory is high frequency ripple doing the damage. There are 2 things that severely shorten the life of electrolytics, one is heat and the other is ripple current. For future ones I will probably fit a 470nF ceramic in parallel.

I have also now repaired a Gen 6 ECU. I can confirm these are a multilayer PCB, and even worse the capacitor holes are connected to the inner power planes without thermal breaks. This means that the only way to get enough heat into the hole to melt the solder is down copper capacitor legs. Once the old capacitor is removed, heating one side with the iron doesn't get enough heat down the solder plug to melt it all the way through to be able to suck it out. I ended up just soldering the new capacitor on the surface and lying it flat with a drop of glue on the reverse side. If I get another one to do, I'll look at getting a surface mount ceramic with the right spacing to solder across the holes.

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 Post subject: Re: ECU repair
PostPosted: Thu Jul 19, 2018 6:32 pm 
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I'm also starting to see it more in different models and have pointed people in the right direction, all gen5 though.
Nibbles you think these capacitors are decoupling capacitors?
Reason I ask is I'm struggling to find the cause of a idle problem I'm having with the CS(hunting when hot)and I am beginning to think it may be an ECU fault. I have seen people refer to the c180 capacitor as the idle capacitor on others forums. I'm going to take the ECU out again the weekend and double check everything is ok and I've not missed other damaged tracks on the pcb.


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 Post subject: Re: ECU repair
PostPosted: Sun Jul 22, 2018 10:11 pm 
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Thanks for the update Chris - very interesting.

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