as99east

I had a p1600 code on my 95 LS400. Company on eBay called ecmguru performed repairs and sent me photos of leaking capacitors. When dealership popped ecu back in for me, code was cleared and so far, car is running fine. We’ll see how it goes though. One year warranty I think. With tax it was about $180 including shipping both ways.

Einzelherz

This may have finally bit my 98 LS400.

Today on the way to the car wash the radio is popping out every couple of minutes for just a second or two. I'm worried it's a loose wire. Then I pull the car into the vacuum station, turn it off, vacuum, and when I got back in, the gages are full dead and no starter. I think the radio was on though. I try this a few times with nothing. Pop the hood to see if maybe the battery got wet, and suddenly it decides to start.

However, the 4 gages are dark and the needles are still. The light on front defroster is blinking for a little bit. The engine doesn't seem rough, but maybe it's a little off. Dash lights seem to be fine (turn signals, etc) and the radio and AC were working. I parked it and put it on a charger cause that's an easy check to do.

I suppose my question is does this seem familiar to anyone? Is there a decent chance the car might leave me stranded until I recao the ECU? I've got the parts, as I attempted it once before. But that time I accidentally lifted a trace and killed the ECU. Had to swap my immobilizer to another which is what is in there now.

400fanboy

Tanin no longer does these repairs .

I'm torn between finding another vendor to send mine out to, or using a local shop I've been too over the years, though they've never performed this exact task before.

What's the general sitrep? This repair is far beyond my skills or tools.

deanshark

Yea uummm, It aint for us common folk.
Don't know if I'd trust someone who hasn't done it before either, it is pretty precise work.
When I was having trouble with my ECU a few months ago, Tannin's website said they no longer repair it. I mentioned that (in a different thread) and they sent me a message saying they still do repairs and thanked me for pointing that out so they could change the website wording. So I'd say give them a call to see what they say.

Or also, a lot of people had good luck with SIA in Illinois for their ECU. https://siaelec.com/
I can't say anything first hand of anyone's work cuz I just bought a used Reman ECU from Denso which works perfect. (got an excellent price) But I have read alot all the years I've been a member here.

400fanboy

Thanks so much for giving me an up-to-date sitrep of the information.

I have a 98 so I'm at less risk - but the more I read about specifically what is going on here, I want to be proactive about replacing my caps. Because I REALLY don't want to have the headache of what would happen were to them leak, kill my ECU, and then now I have to transplant a new ECU and deal with the immobilizer and all that jazz.

So I just made some local calls around town. Learned some interesting things. I talked to my mechanic who bounced me around to a few people.

There used to be ONE guy who would primarily do this sort of work in the area (city). All of the independents would use him. Nut he went out of business and there isn't really anyone in the city anyone knows of who does board-level soldering work. The demand for it is so low, the shops either turn it away or mail the stuff out. My mechanic can do basic wire-level stuff, but not to the level of familiarity that you'd want for our ECU repair.

What's interesting though - the final electronics shop I spoke with said they have used https://modulerepairpro.com/products...xus-ecu-repair multiple times. Mostly with Chrysler products in their experience, but they've always gotten back quality work from them (says the one guy). I took a look on their website, and they do have services for the 92' - 95' LS400 ECU. Their website doesn't mention capacitors or not. But it's an interesting thing I found I figured I should document here.

ankurdave

Thank you for this excellent writeup! A few months ago I replaced the ECU on my 1995 LS400 (California) with a used one from eBay (89661-50235) to fix the off-throttle shock issue. This ECU worked perfectly and all capacitors looked OK, but this week I decided to replace them anyway as a preventative measure. I don't have much soldering experience, but I wanted to do it myself, and it seems to be a success. A couple notes:

1. All the recommended 47uF capacitors are out of stock, so I substituted the 63V Rubycon RX30 63RX3047M10X12.5.

2. During desoldering, I had a very hard time getting the solder out of a few of the through-holes/vias. My Engineer SS-02 solder sucker was hardly able to pull any solder out. Eventually I was able to make a small tunnel through the stuck solder by heating it and pushing a sewing pin through.

In hindsight, I'm guessing that the board's factory protective coating was "sealing" the solder in at the other end of the hole, so I could not suck it out. The stuck solder became difficult to melt, I think because of contamination from this coating. Is this a plausible explanation?

If I had to do it again, before starting to desolder, I would thoroughly remove the protecting coating from both sides of each hole using isopropyl alcohol and a bristle brush.

andymane

So here recently I've done a timing job on my vvti SC and am having a misfire on all bank 2 cylinders. After doing some diagnostics I got to the ECU and belive I may have a leaky capacitor or two. Does anybody know of anyone who can rebuild one? Been working on this car for awhile and just want to drive it soon.


Just looks like it got leaked on

Petan

Hi, I have LS400 1992 more than 500 000km on it. I read lot of forums, discussion and need some advice.

Few monts ago ABS and TRAC light come on. Steps done and notes:

1) ABS and engine ecu error codes check - no code
2) ABS code check, two times blinks than can be hear relay close to bumper switch off And ABS and TRAC light get on.
3) Tried wheel sensorts check mode, after shift to D or release parking brake fast ABS light flashing (check mode activated) ABS light go on. No codes.
4) Changed ABS ECU by same - no change, same issues
5) Relays under glove box close to ABS ECU switch on when ign go on and holt till ign is on
6) TRAC second trottle selfcheck active when ign on
7) ABS sensors in wheels checked by servis - no failure
8) TRAC high pressure pump and relay not switch on, no pressure in accumulator, but can be caused by not working ABS?
9) brake pedal when is press and engine run is very slowly going down

Any advice what to be check?
abs actuator not working?
Or some ground point?
Or can ba cause by bad capacitor in engine ECU (checked looks ok, not changed).

Thank you

Emmetth

Can you use the same capacitors that you would use for same year ls400 to rebuild the celsior ecu?

LeX2K

As long as the values match, yes.

Entropic86

Here's my personal case where new ECU capacitors did not solve anything. Just a data point for anyone interested:

1999 LS400, 200K Miles, Spent it's whole life in Tuscon's 100+ degree summers. New to me this August.

Relevant symptoms:
-Tachometer and speedometer frequently would not work, then randomly start working perfectly in the middle of a drive (not solved by new electrolytic capacitors)
-Rough midrange 1500-3000RPM (turned out to be solved completely by a new rear engine/transmission mount)
-Slight smell of fuel or NOx from the exhaust even when engine is warm (not solved by new electrolytic capacitors)

All the capacitors in the ECU were replaced with the first recommendation, longest life, high temp, low ESR capacitors from Digikey & Mouser.

The soldering was done by a friend who has done advanced surface mount and ball grid array soldering for a living for 15+ years.

Capacitor replacement did not fix my issues in this case. In fact, the car runs just as it did before.

I just wanted to offer this up as a data point for anyone thinking about paying big money to have this done. It hardly cost me anything except some time (I ended up buying all the capacitors in quantities 10 times greater than needed because they are so much cheaper when you buy 10+). After reading much of this thread, I'm glad this is something I can eliminate from any foreseeable troubleshooting in the SFI system, but it changed nothing in my case.

Good luck all!

heyTony

I have followed this guide and have found it to be sound with the 1998-2000 capacitor list. Thanks for that. I used Mouser for the capacitors as they are closer to my location and have had nothing but good results from them. Their website makes searching and comparing easy to do.

The reason for my repair was hard-start symptoms, but it had also fixed other issues I was not made aware existed to begin with. Things like the AT shifting erratically, now shifts as it should and feels like it should when before, it would hang-up to high-RPM before it finally shifts or doesn't down-shift to the appropriate gear for the needed acceleration. So that was solved. Engine also seems to be behaving more responsively when before, it would feel sluggish or low-power. I researched that the ECU was responsible for fuel-supply to the fuel system during key being moved to ON/START position so this may have solved it. Before, the engine would hesitate to fire up even though it was cranking. Random check engine light codes also started appearing which have nothing to do with my starting issue. It works and the immobilizer/key codes were still intact after the repair. Here is a photo with the new capacitors installed:




The big 330uf one was a surprise as the replacement was significantly smaller compared to its original as well as these 47uf capacitors with the long-life replacements being significantly larger. I had the ECU repair done by a "board-level" technician locally and he was able to professionally replace the capacitors. Though he did slightly hit one of those 47uf with the soldering iron on the edge there but just barely. Should be alright. I have attempted this repair myself to no avail- my tools, though professional-level as well, was not to this required detail and after the attempt had decided to let the technician do it for me.

Capacitors used:
EKZE500ELL100ME07D
EEU-FC2A470
35ZLH100MEFC6.3X11
100ZLJ33M8X11.5
EEU-FR1H221
UEP1H470MPD
35ZLH330MEFC10X12.5

Yamae

Thanks Tony for the report.
Other than the common problem of erratic AT shifting among 98-00, you were experiencing hard-startings and others. Congratulations on your fix and also on the more responsive engine. It's been almost a quarter century since the production of a 98, it will be natural that owners of a 2.5 generation of LS400/Celsior may have capacitors problem.

heyTony

Thanks Mr Mae for all the help during all these years. Your posts help keep my old LS400 alive- things like the door lock motors and the bulb warning board fix for LED tail lamps. I hope the engine control module lasts for a while with these new capacitors.

Jake07

Hey fellas, i am having issues with my '96 ls400, I'm beginning to think it may be an ECU problem. Just wondering what you all might think it is, or if anyone has had similar problems, and repairing the capacitors has solved it or not.
My 1uz has been running great the past thousand miles, (a little over a thousand miles back i did a timing belt/water pump replacement) and had 0 issues. Out of nowhere yesterday my car wouldn't start. it would crank, but wouldn't start until i gave it a healthy shot of starting fluid, and it fired right up and ran fine. Couldn't think of what might have been the problem. Fast forward about 2 hours, on the highway, my cruise control starts acting a little funny, the rpms began to dip and go back up, and started to lose power. i pulled into the nearest gas station and it was still doing this sputtering and rpm fluctuation thing. i left it at the gas station and came back for it that evening and it wouldn't start even with starting fluid this time. Towed it home and now this morning it started right up with no problems at all and not sputtering or anything. At first i thought this was maybe a fuel pump issue, but now thinking it may be the ECU? I noticed this thread about a year ago and was wondering when mine would start acting up. This seemed to sneak up on me though. I can't pinpoint what it could be and unfortunately don't have money to throw at it right now. Any advice or opinions on if this is an ECU problem or not, would be helpful. thanks.
and my apologies if there would have been a better thread to put my sob story in