Barbary

Thanks Duck, good advice. I just did a 750 mile trip, everything went fine after I'd been back the CEL came on. Your right a 300,000 mile 30 yr old car.

ObSCessed

I went through this same egr fiasco , I replaced that valve 3 times, cel never went away, finally replaced ecm, and has been fine ever since, I think you should seriously consider getting a spare ecm or having yours recapped I have the feeling that’s it

KahnBB6

iTrader: (5)

^^ THIS.

Joe, check through this thread and verify your ECU part number for your model, year and emission type. When you pull up the passenger side carpet slightly and remove the plastic protective cover you will be able to see your original ECU and check that the part number matches.

It will be best to physically look at the part number on your 1992 SC400's main ECU in order to make sure you can source another one of the same kind.

https://www.clublexus.com/forums/per...s-by-year.html

Aside, when you remove it I highly recommend that you use some totally clear packing tape strips (just enough of it) to fully cover over the original thermal paper sticker labeling that Toyota used for these ECUs. Those stickers tend to fade and rub away with time so the application of 2-3 pieces of overlapping packing tape tends to keep the original printing stable from now on. Also, copy down all the information on the label and use a little labelmaker office tool to print out the Make, Model, Year, Trans, Emission Type and Part Number of the ECU and stick those DIY stickers on the front of the ECU panel as well. This helps ensure that you can always go back and identify exactly what ECU you are looking at.

Then I would get both the 2nd spare good working ECU capacitor serviced (unless it can be verified that it was already serviced with new capacitors) in addition to the ECU that is original to your SC400.

Tanin Auto Electronix and SIA Electronix can do this for you. Make sure you put enough insurance on the package. I recommend you avoid using Fedex Overnight or any "overnight" shipping option as the slightly slower ones and standard ones are more reliable.

Barbary

Good News! at least for me. The CEL hasn't come on for quite a while. Its actually been hard to tell. Weather in our neck-a-the Woods has been tough, been difficult just getting out of the house basically since Christmas. Moab's Main Street is a river. The Vegas strip was a river a few days ago. Its been difficult just to get out of the house to drive, but I have some, even test drives and no engine light.

When the light 1st came on I took it to a shop in this small town and he asked me where I got gas? I had drove back from Durango and Monument Valley thru some pretty rural territory. He did say I may have got some bad gas. I got him to run the lights code-71 the ERG valve and went round & round w that mess. Really didn't come on for long at all when it did.
Went back to him for an FYI and he said it might well have been the gas and that good car computers have a way of self adjusting.

So here I am w a 30 yr old SC driven everyday of those yrs with an ECU that is still capable of, (probably what happened) self adjusting the car. The Bullet blows me away every day. One of the reasons I called it Bullet as in "Bullet Proof" long time ago. Its running great now, always has.

I mentioned what happened when my alternator finally died on me in front of an auto zone store in Albuquerque testing the alternator and this 30 something guy comes up and telling me and everyone about my engine and car. Like the 1UZ is considered one of the best engines ever made. Then he mentioned something I had never heard, that I only do maintenance never repairs!
I thought of that and he was right. I have never done a repair, except my door hinge, (my windows still go up snd down). My a/c condenser was installed in Japan, have never touched it.

All that has given me the belief "If it ain't broke don't fix it". I'm not even going to look at the ECU because I don't know where it is. I never have had to know where it is. I'm not even going to breath on it. I was at a Loves service station recently getting gas and one of the workers, younger guy, comes over and starts gushing about the car in front of everybody. He probably knew more than I do. In fact I asked him how he knows all this stuff, he just said he was a car guy and said he owns a Beemer. I said I have never made a repair on the car and he kinda looked a little sick and he believed me. He's probably done a few repairs.
I do the basic maintenance, replace worn out stuff, nothing fanatical, except for keeping it clean and looking its best. That I probably am fanatical