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This info was copied from the ECU thread.
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As far as I investigate the variation of the ECU for the North American market, there are ECUs as follow.
ECU Part Number USA/CND Some for Taiwan
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90-93 model
Part Number, Production Date, Model(Description)
89661-50010, 05/1989-08/1990
89661-50020, 05/1989-08/1990 W(TRACTION CONTROL)
89661-50030, 05/1989-08/1990 CALIFORNIA SPEC
89661-50031, 08/1990-09/1990
89661-50032, 09/1990-08/1992
89661-50040, 05/1989-08/1990 CALIFORNIA SPEC & W(TRACTION CONTROL)
89661-50041, 08/1990-09/1990 W(TRACTION CONTROL)
89661-50042, 09/1990-08/1992 W(TRACTION CONTROL)
89661-50140, 08/1992-01/1993
89661-50141, 01/1993-08/1993
89661-50142, 08/1993-10/1994
89661-50150, 08/1992-01/1993 CALIFORNIA SPEC
89661-50151, 01/1993-01/1994 CALIFORNIA SPEC
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So I thought all 90 to 92 ECU's would interchange that is if you have trac it needs to be trac ecu.
So how come some 92's fit 93's?
So does it mean that a 89661-50020 will interchange with a 89661-50042 ?
There always were minor changes. Regarding the compatibility between different year models, Toyota/Lexus would clearly say, No. They'd say, "Use the same one except the one explained in the TIB".
Those who use a different ECU may kill their car in the worst scenario. But sometimes it shows a good result like to use a 96 ECU to a 95 model. It often improves the engine halt problem after the long high speed run.
So will the ones I mentioned interchange?
For that matter will all that say 90 to 92 interchange. Or are you saying we need to keep the production dates the same?
These are the stock number listings and they match for all Trac 1990, 1991, and 1992 I did not look at 1993.
In other words these same numbers were listed for each year I called up, and a perfect match.
So at least for the Trac ecu's they are all interchangeable in the years posted.
I'm glad because I have 2 spares that are 50040 and the one out of the high mile 90 is a 50020.
Are you sure that the Atlanta site is fully authentic?
As I asked a friend of mine, in 1992, there were many big design changes such as the cold start injectors and the timer for those were not used any more. O2 sensors with a heater were also introduced. The evaporator system was changed too. How can the ECU handle those differences?
What ? Cold start injectors ? The 1990 has them. And for o2 sensors I just now looked on rock auto for Denso numbers, it is the same for 1990 and 1992. Now maybe in the JDM Cars all that was done I don't know. But the US ones are all the same any minor changes will be mention in the New car features book. The Atlanta site is a Lexus dealer so why wouldn't they be authentic? So just removed the front wire cover off my 92, it has the thermo switch for the cold start injector, and I also looked in the 1992 volume 1 shop manual and the component location picture shows a cold start injector.
There are some very small changes from 90 to 92, I think dual piston calipers were the big thing.
What ? Cold start injectors ? The 1990 has them. And for o2 sensors I just now looked on rock auto for Denso numbers, it is the same for 1990 and 1992.
Of course the 1990 has them because it was in 1992 when cold start injectors were deleted. I often find that Rockauto sells something very strange. For an example, they sell spark plug cables for a 98 LS400. How can I trust them fully? http://www.rockauto.com/catalog/x,ca...,parttype,7224
They list up something peculiar and I had many bad experiences with their list buying parts for a Mercedes 96 S500 which requires me to fix several times more often than my Celsior.
My 1992 shop manual shows the cold start injector.
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90-93 model
Part Number, Production Date, Model(Description)
89661-50010, 05/1989-08/1990
89661-50020, 05/1989-08/1990 W(TRACTION CONTROL)
89661-50030, 05/1989-08/1990 CALIFORNIA SPEC
89661-50031, 08/1990-09/1990
89661-50032, 09/1990-08/1992
89661-50040, 05/1989-08/1990 CALIFORNIA SPEC & W(TRACTION CONTROL)
89661-50041, 08/1990-09/1990 W(TRACTION CONTROL) 89661-50042, 09/1990-08/1992 W(TRACTION CONTROL)
89661-50140, 08/1992-01/1993
89661-50141, 01/1993-08/1993
89661-50142, 08/1993-10/1994
89661-50150, 08/1992-01/1993 CALIFORNIA SPEC
89661-50151, 01/1993-01/1994 CALIFORNIA SPEC
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So the above bold listing says this is 1990 through 1992, if something was discontinued in 1992 how come the same ecu was used?
My educated guess on this date deal is, there maybe some hardware and software updates from what the old 89661-50020 unit had, since all the other engine sensors and wiring remained the same, the newer units would be backward compatible and the new units would then contribute these new updates into the older manufacture date cars. Updates could be various operating regimes, fuel maps, timing etc.
(that is simply the same one but the box is upside down).
I know the name and type of these style connectors in these pictures, but nobody knows the name of the second style from the post I linked. Even the resident "experts" are completely baffled, LOL!
I suppose the connectors would be a good indication of whether the ecu would work in said car or not. If Lexus was going to not have newer ones downward compatible then why not make it idiot proof and use different connectors. So are the connectors different from a Trac ecu versus a non trac ecu?
10-18-15, 04:20 PM
ECU interchange ?
