ECU Capacitors

I will try again has anyone in the UK actually had new capacitors fitted to there ECU if so where and how much.

I looked at my ECU some time ago as it seemed fine, but am now thinking that I'll change the caps soon as they are old and it would get the job done.

The first thing is to identify the old ones, so I opened mine up and took a look.

1996: 1KZ-TE A/T

* 175800 1336Y *
======================
Engine Control TOYOTA
----------------------
89661-26170
======================
175800-1336 12V

ND Nippon Denso made In Japan
[    26P    ][  16P  ][ 12P ]

C001  47 uF  63V SXE
C003  33 uF  35V Nichicon
C006 100 uF  10V Nichicon
C008 220 uF  10V Nichicon
C211   3.3uF 50V Nichicon
C402   1 uF  50V KME
C424 100 uF  50V KME
C425 220 uF  50V KME
C601 100 uF  10V Nichicon (Daughterboard)

So there's a total of 9 caps in mine, just over half of them are Nichicon. The worst thing is the number of 10V caps, in my view at least 16V parts should be used. So I plan to up-rate and upgrade to new ones. Capacitance must be the same but voltage can be higher.

All caps are 105C grade. Sourcing from Farnell rather than eBay is suggested as they are more likely to be genuine quality parts - no point in going to all the trouble to fit fakes i there.

So the plan is to order new ones and then replace them carefully one by one until done.



I don't know who can replace them, what you need is a decent technician at a local electronics firm as reworking boards like this is their bread and butter. I'll probably have a go on mine myself and see how it goes, it looks a good quality board at least a;though I think the legs are folded at the back so they may need to be 'walked out' with a soldering iron, then the holes solder sucked and the new ones will be easy to fit. It's always worse trying to get the old stuff out - that's where the risk of damage is.

Now I need to order these, at least during the week anyway.

Good advise and pics I am not up for DIY on the ECU have called three places locally they just want to replace the ECU at up to £900 if they can get one, have only found one place Blue strike near Birmingham they need ECU number to give a quote I need someone a bit more local so I can deliver

I've ordered the caps from Farnell, the best long-life ones I could, perhaps there's a better selection to be made but this is what I ended up with

ECU Order list: Farnell/Element14. S = Space restricted.

Qty  uF     Reqd_V    Caps              Makers_Part            Farnell_Order
===========================================================================
1    1uF    50V       C402              ECWF2105JA 1854891 (PP film capacitor 250V non-polarised)
1    3.3uF  50V       C211              200LLE3R3MEFC6.3X11    2342093 (Rubycon LLE 12-20,000hr)
1 S  220uF  10V       C008              35ZLH220MEFC8X11.5     8126690 (Rubycon ZLH  6-10,000hr)
1    220uF  50V       C425              50ZLH220MEFC10X16      8127093 (Rubycon ZLH  6-10,000hr)
3    100uF  10,10,50V C006,C601,C424    50ZLH100MEFC8X11.5     8127077 (Rubycon ZLH  6-10,000hr)
1    47uF   63V       C001              EEUEB1J470             2079115 (Panasonic    5-10,000hr, 63V, 15x8mm)
1    33uF   35V       C003              100ZLJ33M8X11.5        2102458 (Rubycon ZLJ, 6-10,000hr)

MoonRoof controller

Qty  uF     Reqd_V    Caps              Makers_Part            Farnell_Order
===========================================================================
1 S  47uF  10V       ?                  25YXF47MEFC5X11        1144619
1    47uF  50V       As above for C001
1    3.3uF 50V       As above for C211


I was short of the total needed for free postage so I added the moon-roof controller - that actually gets cooked in the roof so it should probably be done too...

I'll see how I get on with mine, it it's straightforward you may be able to pop by one day and I'll replace yours too for a contribution toward the parts, but no guarantees and you'll have to dig it out of the van .
No guarantee it will work afterwards either of course, we'll see how mine goes first!

It would be nice it we could get spare ECUs but I don't know where to look, it also has A/T written on it so it needs to be for the Hiace rather than a Hilux too i suspect.

I do now have 5 sets of capacitors though as the min order on many is 5.

Hi thanks for the offer keep us up to date on the replacement unless I can find someone local to do the job I may leave it alone (if it aint broken dont fix it) .

Looks like my caps will arrive Thurs or Friday as Farnell is super fast. I had a go at changing the only Nichicon on the sunroof controller with a new cheap cap I had spare, the bent legs do make them a bit of a pain to remove so I may take the ECU boards out of the metal enclosure to do them so I can cut the old caps off with wire cutters and take out each leg separately.

Various ways to remove them are discussed here:
https://www.eevblog.com/forum/repair/desoldering-electrolytics-with-bent-leads-on-old-boards/

It's really all in the removal of the old caps and basic PCB handling, soldering in the new ones is the nice easy bit.

It's always a good idea to leave working stuff alone, I've a long list of Van jobs I'm working through so I'll be happier if it was all done before I start sticking all the trim back in - one less 'to-do' on the list! .

I've been wiring in the rear fog lamp (red LED in the RHS reversing lamp position), reversing camera, head unit, car alarm + remote locking, also adding some insulation and sound deadening to go in. Also Washing the headlining and sliding sunroof shades outside of the car with a bio-washing spray and wet vac so for me it's just another thing to get done, in your position with it working fine and all the trim in place I'd leave it alone until you suspect it or lay it up for a refit.

I'll keep the spare caps handy anyway - to do the job properly you need long life 105C parts and I'm quite happy with the selection I ended up with, they're certainly better caps than it had when new and better than a repairer may have access to at short notice, although an ECU specialist will have good ones too.

I've made a small edit to the parts list; As I was changing the caps today I noticed that C402 is a non-polarised cap (KMW-BP series) so you don't want to be putting a regular polarised one in there.
I had some PP (polypropylene) 1uF 250V caps to hand so I used one of those. It's a bit overkill to use a PP (far better tolerance, lower leakage, higher current etc) but it will do the job better and last forever. All the rest are polarised.

I'm finding the best way to get the old caps out is to unbend one of the pins on the back of the board with a soldering iron and small screwdriver, then (after a few seconds of cooling time for the board) heat that pin again while gently pushing the cap over as far as possible (when it's melted!) to remove that lead. Then bend that (now free pin) out of the way, bend the cap back and then melt the 2nd leg while gently pulling the cap off - that one will come off very easily.

One way I found that clears the old holes is with a low impact solder sucker. This does however disturb the 'conformal coating' (special varnish) used on the board, so the last few caps I just used solder braid and cleared some holes with the new component leads, melting the solder with a new blob of solder as I pushed the component it. In future I'll just use braid I think as the coating is happier that way (and solder doesn't get stuck in the coating!).

Also C425 was stuck down to the board so that was fun to get out, I used braid to clean the holes out and centred the legs with the soldering iron tip and then spent a patient few minutes rocking it as it gradually loosened off and was able to drop out.

I'll test it in a few days when I finish some other bits, it's back in the van now! Not a particularly trivial job and not one for new DIYers.

Well it was a nice windy day today and I'd stuck a few bits back into the van so it was ECU test morning.

And it works just fine!!

So that's a successful operation. I do wonder how many techies spotted that C402 was a bipolar/non polarised cap, but obviously the PP I fitted is working well.

Started first time after a few months of sitting there too, which is nice. There have been a few reports of bad starting with poor condition batteries, as a simple electronic engineering point: If the caps are leaking (electricity) and dragging down the voltages within the ECU to the extent that faults are noted in normal driving (when B+ will be around 14.5V it's not surprising that when it gets 9V or so from a loaded battery turning the engine over then it's not going to work at all (i.e. it's not going to start).

A fresh battery will probably hold 11 or 12V when cranking the engine, a tired old one perhaps 8 or 9V, so some of these 'needs a good battery to start' stories are perhaps symptoms of failing caps.

GPW congrats on your success I find you comments failing to start caused by a poor battery interesting this was my conclusion last year when my 3ltr did exactly that at first we suspected failed capacitors but realized what a massive voltage drop occurred with heater plugs and starter cranking, replaced the duff battery no failed starts since.

Cheers!

I'm currently doing quite a bit of work with voltage regulators, the buck (drop-only) ones have about 1V min drop, so if you set the output at 12V then from 35V to 13V you get 12V out, then at 12.5V in you get 11.5V out, 12V in 11V out etc.

I then discovered that boost/buck converters were available to hold my 12V from 35-5V so for some lighting I may use them.This is what made me think that perhaps as the caps get leaky there is a gradual deterioration of starting ability.

BTW I have converted my big interior dome lamp lamp with a boost/buck converter and LED strips and it's spooky how totally unaffected by anything else it is now. Even starting the van: it just sits there without a tremor.

Sorry GPW you have totally lost me on electrics did not start learning till late in life every thing was mechanical when I started motoring too old to change.

Apologies

If you imagine a voltage is equivalent to the height to which a water butt of water is filled you have a good analogy to voltage.
When you open the tap at the bottom the speed at which the water whizzes out of the tap is the equivalent of current.

Note: The total amount of water lost is the energy equivalent to electricity - i.e. capacity use of the battery.

The idea of a regulator is to create a smaller height of water, like adding a bucket with a float valve to the water butt. As you can appreciate the float valve only works if the water level (voltage) of the water butt is above the water level (voltage) of the bucket - as water can't flow up hill.

At the bottom of the butt and bucket (ground/tap level) there is a pressure related to the depth of the water above it. Too much pressure and you'll damage the tap: too much voltage and things get damaged in a similar way.

That's really all there is to it, a regulator like in the ECU needs a higher voltage above it to make it work. In the leaky capacitor case your small bucket has a hole in it: so as it gets filled from the water butt the water level in the bucket can't rise to the correct level as it has a new hole in the bottom which the filling tube was never designed to provide the flow of water for. An old tired battery is like a water butt in the middle of a dry summer, some comes out but the hole in the bucket is more important than it was in the winter when the butt was full (like a new battery).

Sorry GPW even I now water and electric do not mix unless your making hydrogen and thats grossly inefficient, but I will keep an eye on those leaky caps thanks for you diligence.

Usually the issue I have with electrics in vehicles is finding the correct wires LOL.
Often there is an inch thick loom of them and I'll want to tap into or interrupt one or two of them

I am learning the Toyota colours though. White with a black stripe is quite often earth, mainly green is often lighting (also locking), orange is often live B+, red/blue and sometimes white/blue is switched live. Brown I can't recall offhand but it does seem that the colours do have a pattern and makes it easier when trying to work out which one might be + when wiring LED regulators on.

We've got an ECU capacitor problem and also told to expect a £900 cost for a replacement. Our Camper, (very similar to JT69). Is off the road until we get it fixed. My concern with just replacing the ECU is that it might not be the cause of the problem but, a symptom of something else going wrong in the electrics. Spending that money only to have 2 blown ECU's wouldn't be good.

-Can anybody recommend a reputable auto-electrician in the West Yorkshire area that could help us with this?

Not near to you but give these guys a call:

https://www.cartronics.co.uk/

Let us know how you get on.

I've just spoke to Cartronics and they confirm my fear that the problem is not the ECU but, more likely to be elsewhere in the van electrics. I can't realistically get the van from Yorkshire to Surrey so they can't help. Many thanks for the recommendation though GPW!

Dougal wrote:

I've just spoke to Cartronics and they confirm my fear that the problem is not the ECU but, more likely to be elsewhere in the van electrics. I can't realistically get the van from Yorkshire to Surrey so they can't help. Many thanks for the recommendation though GPW!

Until you get the capacitors in the ECU changed all bets are off. It's a known problem. The symptoms are usually a ticking noise when the van has broken down and it only running for a few minutes at a time.

Cartroniks are obviously unaware of this, you simply need a get a price for them to change the caps and to do a postal return service for you before inventing new and other problems. If the capacitors haven't failed already they will fail anyway, you've got to get them changed - there's no way around that.

No need to discuss possible faults etc with them, simply get a price for doing the job, that's all you need to be interested in at this point. Something like 'Leaking capacitors are a known fault with my ECU, I'll like to get a price for you to change them please, so I know the ECU is working properly'.

It's pointless trying to diagnose the van with a known fault sitting there, you'll be chasing your tail!! Lots of 1990s Hiace ECUs have failed, changing the caps always fixes them. Go for it!

Hi There
GPWs advise is spot on its a known fault on the ECU throws all sorts of symptoms but having said that I asked a few places big and small nobody had an exchange ECU, and as for repairs the trouble is they want to charge hundreds of £ and the actual repair costs maybe £50. The story usually went like this yes we can repair it but cannot because we do not have the correct test equipment so not prepared to do the job. Your best bet is as I did is to find an enthusiastic amateur with good soldering skills, the capacitors are readily available £2 each, the actual cost no more than £40 and to test it just put it back in the SC and turn the key, before you ask who did mine, sorry they do not wish to have a queue at there door.  I was so so lucky.
PS Have sent you a PM

Hi Guys, Can you help?
I've been able to find an electronics house that can replace the faulty components on our 1KZ-TE 89661-26170 ECU.
-Can anybody let us know what the value & type is for the C226 Capacitor?
P.S. Cartronics were unable to help, many thanks GPW for the suggestion

Some pictures below to help
https://drive.google.com/open?id=1jvHSUrk0x8LAN5xGo4TrfTinptIC1nLf
https://drive.google.com/open?id=1HgSbLPFPffjd2zm9n93puGH7ZrK2FcNL

Ouch! That one has really burnt up. Hopefully someone with a similar unit can have a look in theirs for you. If I was faced with that I'd draw out that part of the circuit and from that make an educated guess but I'd have to have the unit in front of me. Pity you're in UK, if you were here I'd have happily looked at it for you.
Replacing the unit would be a temporary fix at best as the 'new' one's caps would be leaking too.

Many thanks AgathaAlice for the suggestions. Without a circuit diagram, capacitor value or specification it's difficult to know what to do. Unfortunately I don't have the requisite skills to make that educated guess. If anybody kind soul out there can have a look at their 1KZ-TE 89661-26170 ECU and let me know the C226 cap value and take a picture so we have an idea of the capacitor type we would be very grateful! :-)

That damage looks beyond regular capacitor failure, so I had a look at the plug wiring:



Perhaps that is the power input, see if that resistor connects to the B+ pin. If so it could have been roasted from it drawing too much current, either due to faulty caps (likely) and/or a shorted sensor.

See if you can use the plug wiring to see if all sensors read at least 10 ohms, you should be able to use a multimeter with one end on the van chassis and one end poking the connector where the sensors are (see diagram). Disconnect the battery first. The diagram I posted seems to have a different connector-letter ref to the socket so also go by the wire colours in the sockets on the van.

If the cap is simply on the input a simple 22nF-100nF would probably be fine. I don't think it failed, I think it was fried by R570. It's the cylindrical ones that fail and leak fluid and power.
R570 looks like it's seen better days, A 1W resistor, measure the resistance across it. It seems to go to A6 (I6) - use a multimeter to check, if you find out and find out the wire colour it connects to in the loom we can see via the diagram what it's supposed to be connected to.

Keep us all in the loop here and we should be able to sort it out.

Many thanks for the suggestions GPW.
-Can you please suggest what type of capacitor the 22nF-100nF C226 would be?
We're thinking that the R570 looks to be a 10R 1W resistor.
Once the ECU is sorted. I'll take it over to the van and try to follow your suggestions and circuit diagrams, I do have a multimeter.
Will definitely keep you posted.
We're so grateful for the help! :-)