First of all, mechanic I am not!
I do my own fluid checks and so on but that's about it. Have seen a lot with various cars through the years, and I do try to get diagnostic ideas before calling in the mechanic.
Our 1995 GS300 has had check engine light on for a long time but ran fine.
Recently it died on freeway. Restarted roughly then would not start after parked.

Trying to read the OBD1 codes so I have an idea how serious, and where to start, but getting nowhere.
I use the wire between Te1 and E1, car in neutral, turn the key on and the CEL just stays solid.
I have tried both the OBD port under the dash and the one in the engine compartment with same results. What am I doing wrong?

 

Try putting it in park.instead of neutral

 

Yes in park, under the dash is the round obd1 port. Make sure you are in the right holes and all the way in. Use a small diameter paper clip as it'll give you feedback as to when you're in the hole correctly. If its solid you are not doing it right. Also be careful what you are shifting in there. There is a lot of other things in there you can screw up if done wrong.

 

First of all, thank you Gensc300 and Nixspeed for your input!
I tried again, in park, using a small paperclip, but with the same non-results.

First time I tried this, I used a large paperclip.
The second time, I stripped insulation off the ends of some copper wire and used that.
This time, I used a small paperclip. Same results each time.

I have a question/clarification, Nixspeed. When you say the paperclip should NOT be solid but should be fully in .... how do I judge that? in the center of each "hole" is a small do-hickey that might be a metal clip. Is that what I want the paper clip to go into?

Thanks to all for any additional info or ideas!

 

Sorry for the confusion. I was referring to the check engine light. It should not be solid on. It should either blink steady and kinda fast or it'll blink the codes kinda like Morse code. The paper clip should be seated in the little metal clip area. Is this a swapped car or just stock?

 

Nixspeed, our GS300 is stock.
.
I've tried this exercise in every configuration I can think of.
So, with the paperclip in the metal clips of Te1 and E1 ...
1) The paperclip in first, the car in park, turn key.
2) Tried it in park with the key on first, then the paperclip in.
3 & 4) Tried it both ways again, this time with the car in neutral.
EVERY time I have just the solid check engine light!
Pretty sure I have the paperclip seated right ... if I turn the OD on,
the OD light blinks rapidly to show that no codes are there.

There must be some engine codes! What am I doing wrong?
Super frustrating.

 

Are you starting the car or turning the key to the "ON" position?

edit: nevermind just saw that the car wouldn't start

 

Sounds like the classic ecu failure.

 

Yep, sounds like a blown/leaky capacitor...mine did the same thing before I upgraded.

 

If it is bad I have a 94 GS ecu for sale that's good. Not sure if its compatible but should be.

 

Thanks, Nixspeed.
How would I figure out if it is compatible?
Looks like I will have to get a mechanic in here to pull the old ecu to inspect for issues, then to install a replacement. Think that is just beyond me.
My husband and I both feel though, that for style, comfort and reliability (before this!) the Lex is certainly worth some effort to fix.

 

Its super easy to swap and I'm 90% sure its compatible. Maybe someone else here can back that up to ease your mind. All you need to swap is a trim tool and a 10mm socket. Its on the passenger floor under the carpet. Just remover the door will plate and peel the carpet back and there is the ecu then just unplug it and unbolt the ecu from the floor.

 

I know on OBDII cars if the cigerite lighter fuse is blown no codes will read, so I would make sure all of your fuses are good before replacing the ECU

 

Thanks, onelt1.
I have checked all the blade fuses just to be sure. All tested fine.

 

Well, shoot. Was all set to find and swap out the ECU.
Before I did, though, decided to double-check. I took the new battery out of one of our classic trucks, and popped it into the gs300. Tried to run the codes again .. and this time it worked!
Very clearly blinked out code 21 (Main O2S & Heater Signal).
How dumb do I feel? Even though I had previously jump-charged the lexus battery, it obviously wasn't up to the 11 volts needed to run codes.
So NOW I need to identify the o2 sensor and replace it.
TIPS??
Looks fairly simple, as long as I identify the right unit, heheheh.