96 LX450 computer replacement question

[Ward Karns]

Due to inattention I reversed polarityed the battery teminals and may have damaged my computer. If I replace it with a used one do I have to have it reprogrammed so everthing plays together properly?

 

[ppc]

Check the simple things first
Most likely the computer is OK but the fusible links immediately connected off the battery may have failed. They supply power to most of the electrical components. Check all the fuses in both fuse boxes, under the hood and to the left of the steering column in the cab. Identify what things work. Like lights, radio, fan etc. And no, automotive computers don't need to be reprogrammed.

 

[Ward Karns]

Check the simple things first
Most likely the computer is OK but the fusible links immediately connected off the battery may have failed. They supply power to most of the electrical components. Check all the fuses in both fuse boxes, under the hood and to the left of the steering column in the cab. Identify what things work. Like lights, radio, fan etc. And no, automotive computers don't need to be reprogrammed.

Thanks,
I checked the fusible links with an ohmmeter and they have continuity and battery voltage is measured on the downstream side, two links I believe. I checked the fuses and didn't see anything blown there. I haven't written down all the systems that work and don't. As I recall, the lights work. The ignition, the door locks, the power windows, don't work. I don't recall testing the power seats. I can't remember what worked or not on the instrument panel.

 

[ppc]

I checked the fusible links with an ohmmeter and they have continuity and battery voltage is measured on the downstream side, two links I believe. I checked the fuses and didn't see anything blown there. I haven't written down all the systems that work and don't. As I recall, the lights work. The ignition, the door locks, the power windows, don't work. I don't recall testing the power seats. I can't remember what worked or not on the instrument panel.

With what's not working, it certainly points to one or more failed links There are 3 fusible links. @jonheld posted the following in a similar thread which there many threads for you to search, including those that made the same mistake as you

Here is a cursory check of all 3 fusible links in system.
This assumes an OEM configuration.

Dome lights working? (FL AM1)
When you turn the key to ON does the CHARGE LAMP light up? (FL AM2)
Brake lights working? (FL MAIN)

If yes to all 3, then all 3 fusible links are intact.

 

[Ward Karns]

With what's not working, it certainly points to one or more failed links There are 3 fusible links. @jonheld posted the following in a similar thread which there many threads for you to search, including those that made the same mistake as you

Oh that should save some time. Thanks again.

 

[jonheld]

Due to inattention I reversed polarityed the battery teminals and may have damaged my computer. If I replace it with a used one do I have to have it reprogrammed so everthing plays together properly?

It is VERY unlikely that the ECU is damaged.
However to answer your question, there is no "reprograming" needed. I would check the build date and the existing part number of the current ECU, and be certain that the part number for the replacement is the same. There were 2 ECU part numbers for the LX450s.
89661-60650 build date 8/96-12/96
89661-60651 build date 12/96-3/97