I agree, I know the 50020 is for the early 1990 LS400 up to date of somewhere around the 8th month that would likely put it into the 91 model year. And the 50042 runs into 92 and I think to the 8 or 9th month. The thing is everything I can think of on those years is all the same, except for front brake calipers. I know 91 at least since I have one use the same number for the ABS/Trac module, So the only possible difference I think would be a possible hardware update and programming, but all pin outs and interface to vehicle would be the same. I guess since there is no real good info on interchange of ecu's I guess I maybe the one that experiments. I need to check the caps etc before proceeding though.
I have interchanged plenty of ECU's over the years. Providing they are the same series/models they generally swap over fine. I even swap between different models / series in some cases when I have a specific requirement. Cheers
What do you mean by series/models? The car it self or the ecu? So far what I know is the numbers I mentioned refer to production date. The dealer site I found had a whole string of numbers for 90 to 92 and those 2 included in it that I listed. For 1990 up to 1992, so I'm guessing that alone would mean all is good.
Bit of both with the model/series. In the early (10Series) LS/celsior the plugs are the same but generally the lexus badged cars have EGR and viscious fan and the Jap toyota have hydro fan , these ECU's still swap over. In the later 10 series they changed the header plug(and oxygen sensors/gearbox plug) but the same hydro/viscious fan work.Toyota Crowns of that era had the same plug as the early SC/Soarer which can swap over in some applications but they have differences between hydro/viscious fans, gearbox temp sensor and oxygen sensor. Then into the 20 series the header plug is the same as the late 10's but they don't swap over (well correctly anyway , I have some come in running very poorly with some very creative wiring). With the 20 series and the similar year crown the header plugs are the same and can interchange providing the viscious fan/hydro fan is addressed. I do a heap of conversions(I have stopped counting as involved in over a 100 each year) so swapping things around is common
What do you mean by header plug? The O2 sensor?
Yeah I agree with you about it should be fine with in the series of car. I'm going to open them up and compare and look for visible problems and may go ahead and try the newer ecu and see how it goes, I have asked this question in emails to a few ecu repair places and no one has answered. I guess they don't know.