I have a 1994 LS400 and I just bought an Obd1 scanner with the correct plug for the car, but it will not communicate with the car. The scanner works, but the computer in the car won’t communicate with the scanner for some reason. I have yet to try the wire method but does anyone know possible reasons for it not communicating?

 

It could be your ECU just not communicating at all. Try http://www.lexls.com/tutorials/intro/codereading.html If it doesn't read anything then it's definitely the ECU is bad.
Read this; https://www.clublexus.com/forums/ls-...capacitor.html and you'll see all the other symptoms of it being bad.

 

Do you know places that rebuild/solder the capacitors?

 

Try the jumper wire method first and see if the car shows you the codes. It could just be that your scanner isn't really compatible with the car. What tool did you buy?

If that doesn't work, then consider checking the ECU

 

Simply check the ripple voltage explained in the FAQ page or check the inside of the ECU first. 29 years old is old enough for those QAS capacitors to leak. I worry that copper traces of ECU board are already eaten some by the leaked liquid which is now very strong alkali.

 

I tried the wire method and it worked, but it was blinking every .25 seconds which means there is no stored codes, but I still have a CEL, I’m kinda stumped

 

I got an old Bosch OBD1 scanner and it wouldnt connect until I realized it needed external power via cig lighter. When it came up, the basic info was pretty useless to what i needed. I will need to reset with the pin / flash counting.

 

I got an old Bosch OBD1 scanner and it wouldnt connect until I realized it needed external power via cig lighter. When it came up, the basic info was pretty useless to what i needed. I will need to reset with the pin / flash counting.