So i have a 1990 ls400 and ive been having some issues with it. Symptoms that i thought definatley pointed to bad alternator.. Changed alternator, new battery, starter tested , tested good, then i noticed the timing marks were not lined up as they origanally had been, so i assumed something with timing, skipped teeth or somethibg.. or cam shaft sensor. Replaced senson checked timing belt everythibg there good. Come to fine out my ecu is fried , short somewherealong the way to the computer. My question is keep in mind i have one key to this car and the plastic around the key with the button on it is damaged pretty bad. Can i get a ecu unit off same make model year and swap it into my car? I think but not sure the security on ls models was changed in 92? So if theres no chip in the key then i shouldnt have to program ecu correct? Let me know what you guys think thanks

 

No key chips, get the correct number on the ecu replacement, if you have trac you need the same.
Its plug and play. The security system is a separate ecu and they all interchange.
You need the correct number for the 90, I think there are 2 different ones, early 1990 and mid to late 1990, the newer one will not work in the older car. Just numbers match it.


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

 

Wow that is great info guys thanks a bunch. . So about the trac, the parts numbers have to match ecu and trac system? Which they are seperate numbers to look for?

 

Those big part numbers will be on the ecu and since the first or left side 5 digits are the same its the right hand
5 digits you want to match. The 50xxx number needs to match, they are very obvious on the tag on the ecu.

If your car has trac you need an ecu for trac. If your car does not have trac then you need an ecu that is not for trac.
I didn't understand your question """"the parts numbers have to match ecu and trac system?"""

For example if the production date of your car listed on the driver door pillar tag is in the range of 05/89 to 08/90 and your car has trac
you will look in the chart for the dates and the number is 50020. That is what should be in the car.

Did you get your ecu out yet? Is it a trac car? And the number is?