No start / Electric Gremlin SOLVED! DTC Codes 14 & 15
 

Hello all! New member here and I'd like to introduce myself and my newly purchased 1 owner 1992 Lexus LS400 with 130k miles. Given its condition, I took the risk, flew into Florida and drove this baby home to Texas on a ~1,200 mile trip without a glitch but when I arrived at my hometown, the car started having problems.

Intermittently, the car would stall while driving in the city or hwy. The RPMs will drop and then come back to normal on several occasions. Through much research on this site, I installed new ECU caps which resulted in a noticeable increase in throttle response but the stalling issue still remained.

A couple days ago, the car decided to give out completely on the freeway and would not start back up again, even though it cranks/turn over. Consequently, I had to tow it home. I pulled the engine codes and got DTC # 14 & 15 which are the #1 and #2 ignition signals. So what are the odds that the two ignition coils fail at the same time?? I started with the basics by looking at the fuses and relays in the engine and driver's side kick panel but all were good. Thinking I did something wrong with the ECU while installing new caps, I pulled it out once again and to my surprise, the green relay next to it called the "Circuit Opening Relay" had a rattling sound to it when I shook it. I then put in a new relay and she started right up and has been running fine for the past 200 miles!

Hope this helps anyone who is having the same problem. The first two pictures shows the defective relay and the last four are pictures of my baby. I named her Crystal ;)


https://cimg6.ibsrv.net/gimg/www.clu...97801dfe99.jpg


https://cimg7.ibsrv.net/gimg/www.clu...901f0b1430.jpg


https://cimg9.ibsrv.net/gimg/www.clu...9f2411bc87.jpg


https://cimg3.ibsrv.net/gimg/www.clu...a8cda1da6f.jpg


https://cimg1.ibsrv.net/gimg/www.clu...e957d72c00.jpg


https://cimg0.ibsrv.net/gimg/www.clu...062cbd92bb.jpg

Looks like you found a nice one. Hope she gives you many more trouble-free miles.

Welcome to Club Lexus:thumbup:

Thanks for posing your fix. Will definitely provide insight for others with similar error codes. :)

Nice find, i know this will help others in the same situation.

Thanks for the report. This certainly will help others.
Congratulations on your success to fix the original problem as well as getting the noticeable increase in throttle response by the capacitors change.

I'm quite interested 2 items you found.
Did you have any chance to see inside of the failed relay and check what part was failed?

Were capacitors looked OK at a glance? Those capacitors tend to have a increased ESR as well as a reduced capacitance. They just look OK but the inside is electro-chemically bad enough when aged.

This is another interesting electrical find. I wonder if this another potential aging issue we'll see more of.

Phantom, ship that relay to Yamae for failure analysis. ;-) (only half kidding)

Phantom,
Thank you for the post - I have a '92 and have been having that exact same intermittent drop in RPMs for several seconds before returning to normal, and it has been driving me batty. I felt it was some kind of ECT/ECM related issue, but it did not occur to me to even check the green relays!!! Will post what my results are next week!
Thanks