Thank you, Yamae!

Sorry, I think I missed your earlier post. I see it now.

 

First of all maybe on newer cars the airbags may have something to do with power train control modules. On these there is no link to airbags that I know of, and I see no reason why the power train module would need any communication with the air bag module. The only thing that distinguishes the ecu's apart on gen 1 applications is if it has trac or not. The reason is there is a separate throttle valve for the trac system to throttle the engine back if needed it even has its own tps. I always thought that the ecu's would interchange from 90 to 92, I tried a newer ecu in a 90 it wouldn't start. And yes I don't know if that one I tried was working or not.
The 2 different numbered ecu's looked the same inside and out, so I don't know for sure what the deal was.

 

Electronics components and circuits can't be checked fully by human eyes. You need equipments and skills to check. An expectation or an assumption alone can't make it possible.

In the late last Century, the CPU giant Intel released CPUs called "Coppermine" series that require the socket called "370". A few years later, Intel released faster CPUs named "Tualatin" series. Both share the same socket 370. Many computer plain maniacs thought that replacing from Coppermine to Tualatin was OK because the socket was just the same. But it was not so because Intel changed the pin assignments some. The changes were just a little bit but the CPU Tualatin did not work at all used at the socket370 for the Coppermine.

There were some real maniacs. They analysed all the pins and signals and found that some pins were just switched as well as the supply voltage was slightly changed. Doing countermeasures for those made it possible to use a Tualatin instead of a Coppermine and succeeded to run the computer much faster.

We should be like those real maniacs to analyse the ECU when we want to use different one although the sockets/connectors are just the same.

 

I know what your saying Yamae, but I do find it funny that they would make drastic changes in the electronics but not the car itself. And the ECU(engine transmission) is the only module that is numbered differently the same number for the ABS module, and all the other ECU's through out the car are the same. Why when all the sensors are the same would they change the ecu, and why would that change affect the car since everything else on the car is the same from 90 to at least 92? I do know there were bigger updates on the 93 and 94's.

 

Just for your information. I have a 1990 ls400 production date 10/89 without traction control.. Original computer is a 89661-50010 and I just tried a 89661-50032. Everything worked fine and maybe just a slight increase in power from 2,000 to 3,000 rpm.

 

Thank you for that information. The ecu I tried is probably not in good shape, I don't know for sure.
So your very early 1989 or 1990 LS400 ran fine on an ECU from a 1992? That is great news.



Yamae you posted this on here awhile back. It had no resolution????
http://repairpal.com/engine-stalling-442

 

There seems to be no resolution in that site but here are two resolutions in the LS400 forum, as you know.
One is to rewrite the firmware in accordance with the TSB and the other is to use the ECU for a 96.