are you guys aware of the need to replace your ECU capacitors?
The following users liked this post:
Curley519 (11-09-20)
12-15-12, 08:12 AM
#33
My 1992 SC 300 had a faulty ECU. Cruise control wouldn't work, fuel pump would stay on with the car off due to a problem with the main relay, EFI circuit stayed powered and got so overheated the car wouldn't start and it drove like poo. Low, rough idle...a number of issues. Bought another ECU off a member here after chasing gremlins for about 2 years and it fixed everything.
12-20-12, 06:01 PM
#35
Can anybody provide a list of what type of capacitors are needed in a 1992 SC300 5-speed? On my ecu 6 out of 7 are unreadable with three having obvious leaks. I know the one at the C504 position is a 105C-100microfarad-10V capacitor.
Update: Found all capacitors needed for this year, make, and transmission.
All of them are 105C
C102 position = 10uF 50V
C104 position = 10uF 50V
C106 position = 220uF 16V
C107 position = 100uF 10V
C504 position = 100uF 10V
C805 position = 15uF 35V
C806 position = 15uF 35V
Update: Found all capacitors needed for this year, make, and transmission.
All of them are 105C
C102 position = 10uF 50V
C104 position = 10uF 50V
C106 position = 220uF 16V
C107 position = 100uF 10V
C504 position = 100uF 10V
C805 position = 15uF 35V
C806 position = 15uF 35V
Last edited by SC300NW; 12-21-12 at 06:10 PM.
12-20-12, 11:25 PM
#36
I might need to do this before I dump $200 on a new shift solenoid. The weird thing about my shifting issue is that the car shifts fine during open loop. But once the engine reaches temperature it shifts like absolute crap or sometimes it wont shift at all from a stop. FSM calls for a ECU test before replacing the solenoid anyway, so I'll check it out and see if I need to replace/repair it.
01-19-13, 10:39 AM
#39
Driver
Join Date: May 2006
Location: FL
Posts: 106
Likes: 0
Received 0 Likes
on
0 Posts
just found this beauty in the ecu.... You guys think I could sent this in to have it repaired or.... not worth it and just get a new one?
Last edited by Pezlo; 01-19-13 at 11:18 AM.
01-19-13, 02:02 PM
#40
Keeper of the light
iTrader: (17)
I redid my ECU a week or two ago, and it was enough of a job that I considered putting it on the LLSF site as an option, but nothing has became of that thought. Takes about 3.5 hours of work, all under a magnifying glass and some bright lights. You need to be able to see every single tracer for inspection. You cannot overlook ANYTHING while in there because the board is covered with an epoxy and it is deceiving in it's actual condition.
05-20-13, 12:23 PM
#43
I thought this only affected older SC400 1UZ ECUs. Now I learn that it also affects 1JZ Soarer ECUs as well as pretty much all SC300 ECUs. Does anyone know if Supra MKIV's and Aristos also have this capacitor issue?
I guess I need to look for a spare one now and send it in to be reconditioned just to be safe.
I guess I need to look for a spare one now and send it in to be reconditioned just to be safe.
10-05-13, 06:44 AM
#44
Moderator
Below is what I wrote for the LS400 forum. A SC400 is not an exception informed by some of members here. That's why I came over here. You will know more at the thread here kindly started by LScowboyLS although it's about a LS400. You'd also better to read the post #487. As long as Nichicon capacitors containing “quaternaty ammonium salt / compounds" are used in the ECU, your cars will be affected. Those capacitors have a ID mark of PF(M) or PR(M).
----------------------------------------------------------------------------------------------------------------------------------------
Toyota has started to use Nichicon's electrolytic capacitors that containing “quaternaty ammonium salt / compounds" in the late 80s and has kept using them for a bit more than a decade. The reason why they used those capacitors was simply because the internal impedance was low enough and showed good performance in removing noise and ripples at DC lines.
A little before that many electronics industries in Japan started to use similar capacitors that were for non automobile use and faced serious leaking problems in the early 90s.
The details are written below but all in Japanese.
http://ednjapan.com/edn/articles/1208/01/news006.html
I don't have the time nor the ability to translate all the contents so I will just translate the title.
“80年代末期の“亡霊”に注意” or “Watch out for the “phantom” in the late 80s”
The “phantom” here means the electrolytic capacitor which contains infamous “quaternaty ammonium salt / compounds". Judging from the title, it is dangerous to use this type of capacitor without taking any special precautionary countermeasures.
Most of the electronics companies in Japan stopped using this type of capacitor in the early 90s or mid 90s for fear of leaking problems. But many automobile industries kept using them because they need good performance. Another reason was that they have been used in high reliability type-capacitors. Nichicon has been manufacturing special versions of this type for the automobile industries using specially coated lead wires with special sealing rubbers. One of my colleagues evaluated them and found the automobile type much better than those types designed for home appliances applications but the lifespan was not as long as those electrolytic capacitors that use regular liquids. Also the high reliability types were very expensive. I cannot show you the details of the evaluation results but what I can say is that the lifespan is longer than roughly 10 years or so but you cannot expect a lot if used for longer than that.
As I fix different ECUs as a volunteer, I came across many failed Nichicon's PF(M) type capacitors these days, some 12 years old, some 15 years old. What I can say now is that my colleague has done a good job evaluating the capacitors using an oven in the accelerated mode.
In accordance with that and from my own actual experience, ECUs older than 12 years are ready to fail someday soon or later, that I can say with confidence.
Below is a failed capacitor used in a 97 Celsior. You can see how the leg has corroded and the part on the board where liquid has leaked out.
Those who want to replace Nichicon's type PF(M) capacitors to avoid future problems, be sure to use low ESR type capacitors. Never select capacitors just seeing the voltage and the capacitance. I recommend you to use Rubycon's type ZLH or Nippon Chemicon's type KZH. These do not contain infamous "quaternaty ammonium compounds" but their ESR is low enough. You also have to pay good attentions against electric static discharge when doing the replacing job. A wrist strap is definitely needed to use. Without it you might damage the ECU.
----------------------------------------------------------------------------------------------------------------------------------------
Toyota has started to use Nichicon's electrolytic capacitors that containing “quaternaty ammonium salt / compounds" in the late 80s and has kept using them for a bit more than a decade. The reason why they used those capacitors was simply because the internal impedance was low enough and showed good performance in removing noise and ripples at DC lines.
A little before that many electronics industries in Japan started to use similar capacitors that were for non automobile use and faced serious leaking problems in the early 90s.
The details are written below but all in Japanese. http://ednjapan.com/edn/articles/1208/01/news006.html
I don't have the time nor the ability to translate all the contents so I will just translate the title.
“80年代末期の“亡霊”に注意” or “Watch out for the “phantom” in the late 80s”
The “phantom” here means the electrolytic capacitor which contains infamous “quaternaty ammonium salt / compounds". Judging from the title, it is dangerous to use this type of capacitor without taking any special precautionary countermeasures.
Most of the electronics companies in Japan stopped using this type of capacitor in the early 90s or mid 90s for fear of leaking problems. But many automobile industries kept using them because they need good performance. Another reason was that they have been used in high reliability type-capacitors. Nichicon has been manufacturing special versions of this type for the automobile industries using specially coated lead wires with special sealing rubbers. One of my colleagues evaluated them and found the automobile type much better than those types designed for home appliances applications but the lifespan was not as long as those electrolytic capacitors that use regular liquids. Also the high reliability types were very expensive. I cannot show you the details of the evaluation results but what I can say is that the lifespan is longer than roughly 10 years or so but you cannot expect a lot if used for longer than that.
As I fix different ECUs as a volunteer, I came across many failed Nichicon's PF(M) type capacitors these days, some 12 years old, some 15 years old. What I can say now is that my colleague has done a good job evaluating the capacitors using an oven in the accelerated mode.
In accordance with that and from my own actual experience, ECUs older than 12 years are ready to fail someday soon or later, that I can say with confidence.Below is a failed capacitor used in a 97 Celsior. You can see how the leg has corroded and the part on the board where liquid has leaked out.
Those who want to replace Nichicon's type PF(M) capacitors to avoid future problems, be sure to use low ESR type capacitors. Never select capacitors just seeing the voltage and the capacitance. I recommend you to use Rubycon's type ZLH or Nippon Chemicon's type KZH. These do not contain infamous "quaternaty ammonium compounds" but their ESR is low enough. You also have to pay good attentions against electric static discharge when doing the replacing job. A wrist strap is definitely needed to use. Without it you might damage the ECU.
Last edited by Yamae; 10-05-13 at 03:14 PM. Reason: To add series names of capacitors
10-05-13, 08:17 AM
#45
Glad to see this thread bumped up as I've never seen it before. Just grabbed my second SC400 last night so I was refreshing up on a few things to do to keep her running great.
Being a 1996 model at 116K do you think it would be wise to do this preventative maintenance on it and replace the caps even if they are still good? I have full maintenance history, and see nothing regarding ECU repair. It is about 18 years old... Driftmotion offers the service of repair for $80+ shipping. Not too bad really, I just don't know where the ECU is located and how hard it is to dislocate it.
Being a 1996 model at 116K do you think it would be wise to do this preventative maintenance on it and replace the caps even if they are still good? I have full maintenance history, and see nothing regarding ECU repair. It is about 18 years old... Driftmotion offers the service of repair for $80+ shipping. Not too bad really, I just don't know where the ECU is located and how hard it is to dislocate it.