Originally Posted by Yamae

I have never heard of the ECU P/N 89661-250TR and it may be a special one and not a standard one. As you see the list below, the only thing I can say is that the smallest value is a 10uF among other all LS400 families. Also voltage 63V capacitors are all 47uF from from 90-00 all models. I can not guarantee but your assumption is probably correct.
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1990-92 LS400 needs 10 or 11 caps as follows:
Qty. 3 of 10μF - 50v
Qty. 2 of 15μF - 35v
Qty. 3 of 47μF - 63v
Qty. 2 of 100μF - 10v
Qty. 1 of 220μF - 16v

1993-94 LS400 needs 8 caps as follows:
Qty. 2 of 10μF - 50v
Qty. 2 of 15μF - 35v
Qty. 1 of 47μF - 63v
Qty. 2 of 100μF - 10v
Qty. 1 of 220μF - 16v

1995-97 LS400 needs 6 caps as follows:
Qty. 2 of 10uF - 50v
Qty. 1 of 47uF - 63v
Qty. 2 of 100uF - 10v
Qty. 1 of 220uF - 16v

1998-2000 LS400 needs 11 caps as follows:
Qty. 2 of 10μF - 50V
Qty. 3 of 47μF - 63V
Qty. 2 of 100μF - 10V
Qty. 1 of 220μF - 16V
Qty. 1 of 33μF - 35V
Qty. 1 of 47μF - 25V (special BP capacitor) - high reliability capacitor, replacement recommended but not critical
Qty. 1 of 330μF - 35V - high reliability capacitor, replacement recommended but not critical

Originally Posted by charlieee3

Hi all, my 94 SC400 has been recently having problems with shifting, so I put car in diagnostic mode and got error code ECT 62 (Shift solenoid 1 valve). So I would only get gear 3 and overdrive in drive position, but could get 1st and 2nd by starting in low gear. I replaced the shift solenoids and the problem went away and shifted well for about a day until the error code came back on. The next step in the repair manual was to check the wiring harness, so I did a continuity test to the solenoid pin on harness that goes to ECU and wiggled the cable around a lot and determined the wiring harness was fine, so the last thing in the repair manual was to check and replace ECU. So, I've opened it up and I've put some photos below.

The only thing I can see that looks bad is the two capacitors in the picture below, what do you guys reckon?

Thanks in advance!

Originally Posted by charlieee3

The only thing I can see that looks bad is the two capacitors in the picture below, what do you guys reckon?

Originally Posted by Oursuda1lab

I think I’m having the notorious ECU problem with my ‘96 LS 400. Runs fine, no starting issues, but sulfur smell when warming up in garage. Then today received the check engine light and had some rough idling at the stoplight. Plugged in my OBD2 tool and had the P0300&P0302 fault codes.

Later it ran fine…?

Should I have the ECU rebuilt or buy one from Flagship 1 ?

any suggestions would be greatly appreciated.

Steve

Originally Posted by Meech

Thanks Yamae.
I did get a code for the TRAC but have forgotten what it was now as my attention was on the non start problem at the time.
I have ordered and am waiting for the capacitors from Mouser at the moment, when they arrive I will replace and se what happens then.
Would you agree that the 0.47uf capacitor that was replaced was most likely a mistake for a 47uf?
I am beat about the ecu part number also. I have tried and tried to research that number but nothing shows. really weird.

Originally Posted by Meech

Hi. First off, great thread and unreal info, so helpful. Hope someone may be able to give me some direction on my car, well my son's car but I do majority of the work on it (ex-mechanic and auto electrician).
We have a LS400 build date on plate is Sept 1994 and located in Australia. Had the car 18 months now and when we had her she seemed to drive fine, couple of lights flashing such as engine light when first started and TRAC light flashing constantly. She needed some other work and so wasn't run much at all. When we got round to running her again she first started to cut out and not start. It would try but die. Seeing as there wasn't much fuel I guessed it must have run out. Put fuel in, cough and splutter and it went but shuddering etc. so thought dirt in the tank been picked up so cleaned tank out.
Car did not run for months then started to use it but it would misfire, backfire and then over fuel and smoke from the exhaust. I fell across this thread (thank you lord) so pulled the ecu and had a look inside and saw that it had already had capacitors changed. I thought I may as well swap them again BUT didn't read close enough so got some random capacitors from the local Jaycar and swapped whatever they had of the equivalent caps. Put it back together and VROOM... she drove beautifully (still TRAC light on though). Drove it for about 6 km then she died and wouldn't start. Left it a couple of hours and she drove back home and died again just before the driveway.
So, I have a few possibilities and a concern on the actual ECU itself.
1) Cheap caps need replacing with quality ones, Digi-Key have all I need and are in my basket as I speak. 9 caps in total in this ECU.
2) One of the caps has not been replaced previously, still has a Nichicon 15uf 35v PF(M) installed so will swap.
3) One of the caps that has already been replaced is a 0.47uf 63v which I am thinking was mistakenly used instead of a 47uf 63v.
4) Which is a big one, my ECU part number is nothing like any of the ones mentioned (that I can see in any post) it is 89661 - 250TR. Does anyone know if this is correct or if not what this unit is from? I tried Googling but nothing really came up. Car ran well for a while when I swapped the caps before but then broke down (possible cheap or wrong caps) so thinking if I put quality caps in it may run ok but wondering if this may be the TRAC light problem due to incompatibility.

Any help would be great, thanks in advance.

Originally Posted by Meech

Thanks again Yamae. Reassuring that you think the same. I will let you know how i get on when i have swapped the caps.