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On my 1993 SC400, my son had a stock ECU and had purchased an "upgraded" ECU. How do I tell what these are and what the differences are? One says, "30" while the other says, "31".
The part number will tell you what its' from. I've never heard of a modified SC400 ECU, but you'll definitely want both of them to say 1UZ-FE. Hard to read the second label with so much being ripped off.
Other than that both of those ECU's appear stock in comparison to modified stock ECU's i've seen for aristo's and supras with the same ECU plugs from Blitz and such.
Thank you! I looked up Toyota ECU part number locations and see that the part number is in the grey part of the sticker, which is almost illegible. Looks like #####-24#30
One of his friends suggested he was looking for an ECU with higher rev limits and different fuel/air mixes. I may never know.
Side note, since all the original ECU labels were printed on thermal paper I highly recommend getting some 100% clear box shipping tape and very carefully laying some over the label so as to preserve what is left of it. Without doing that the printing on the label's surface will eventually deteriorate even further to the point that it will not be apparent what it used to say the ECU type and part number are.
Stabilizing original ECU labels in this way is what I have done with any that I own.
I don't think the big number is important and have never heard of them being different anything rev wise or like that.
I do know there is 92-94 year range ecu's and 95+ and you do not want to mix and match them or it won't correctly, there are injector wiring differences between those years.
If it has the same part number, that is the going to run like it is the same ecu given they are both still working.
edit*
can't see the small number but if the small number ends in 31 it would be the same ecu for 92-94 sc400 that replaces the 30
This website says 89661-24231 is a replacement for 89661-24230
If this helps to identify anything we do have a mostly complete (but not 100% complete) list of 1992-2000 SC300 and SC400 ECU part numbers sorted by model, model year, emission type and transmission type in this thread:
I took a 94 ECU out of a yard and put it into my 93 once and it drove fine for a few hours, eventually ended up idling at 300, and later on the car wouldn’t start without giving it gas and would refuse to idle without gas. Could’ve been that ECU but I wouldn’t recommend driving far after switching the ECUs
I took a 94 ECU out of a yard and put it into my 93 once and it drove fine for a few hours, eventually ended up idling at 300, and later on the car wouldn’t start without giving it gas and would refuse to idle without gas. Could’ve been that ECU but I wouldn’t recommend driving far after switching the ECUs
^^ Yikes! This sounds like that junkyard ECU was experiencing capacitor issues right off the bat once it went out of closed loop mode.
OP, I would add to Broken93's post that finding a good working ECU is the starting point and directly after that the capacitors need to be replaced due to the age of all the ECUs from this era. They could be failed or worse have leaked electrolytic fluid on the board or they could just be getting old, tired and lazy. In most cases new OEM-spec and OEM-supplier brand capacitors (sourced from Digi-Key or Mouser) bring our old ECUs back to 100%. You never know a junkyard ECU's history but this is what usually makes most of them perfect again. It can be done DIY if you know what you're doing and have the right ESD-safe tools or through a specialist like Tanin who offers it as a standard repair service.
Sounds great. Since this car will be down for work for awhile, I'll immediately start on the tannin process. I can send them the ECU, have them spruce it up, and put it in when the engine work is done.
UPDATE - was replying to another thread and saw this. The '93 SC400 is currently sitting at a friend's yard up in the desert near Palm Springs. I do hope to get back to it, but have other priorities, such as working on my '99 daily driver.
11-04-20, 09:23 PM
ECU Question
