sugon

So Idek where to start.
I have a 1997 Ls400 with 173k miles. I’m the second owner and bought it from an old guy who took decent care of it but didn’t baby it either.

last week my abs light has been on so I bled the brakes and cleaned the speed sensors. Tried to use a innova 3701 scanner to bleed the abs, which didn’t work and continued to say no communication. I tried jumping the diagnostic port to get abs codes which I had previously gotten which were 41 & 49, but now won’t give me any codes. Went to take it out for a drive anyways just to see if the regular brake bleed ( not the abs bleed) made any difference and she wouldn’t shift out of park. figured she was just being dumb and pushed the hidden emergency button by the shifter to put it in drive and immediately noticed issues with my engine bogging at 30-100% throttle , but it would start run and drive. now today it starts But stalls/dies after 10 seconds or so without putting it in drive or anything. I still can’t get any codes or diagnostics.

I’m so confused at this point I don’t even know where to start because I’ve had no issues until recently when the abs light came on.


I did some research and had previous heard about the whole ecu capacitor issue and just took mine out to look but all the caps seems good. Any one have an idea what the issue could be? Also can the ecu capacitors be bad but look good with no corrosion or leaks? Thanks in advance

400fanboy

Your symptoms do sound like ECU issues. Intermittent, drivability, shifting problems, inability to communicate with ECU.

It's possible to have defective caps that haven't started leaking (yet). The definitive test to say forsure if they are bad or not is the following:

https://www.clublexus.com/forums/ls-...-by-yamae.html

sugon

Okay thank you. I’ll try to find that capacitor to test it and hopefully will get some results. I was thinking about having a friend with a 97 pull his ecu so I could try it before buying a rebuilt one

400fanboy

Unless the part number is the same, you cannot swap ECU's. Also, 1997 was the first year of the immobilizer. You cannot swap ECU's.

ECU part number list is in this thread:
https://www.clublexus.com/forums/ls-...capacitor.html

This failure is inevitable on all ECU's. You can't just swap in a used one (unless it's been fixed). If the ECU has an immobilizer, replacing the ECU is... difficult. Far, far easier to rebuild it.

For 96 and earlier cars, I'm not familiar with sources of rebuilt ECU's which have been repaired. Most people repair their ECU rather than buying a rebuilt one.