Kcm5899

Like I said, I am new to Club Lexus, but have been a member of Toyota forums for a few years. I have a 95 ES300 that I have been using as a daily driver for about 5 years now. It has 282k miles on it and I've been scratching my head to do what I can to get the old girl to 300k. I have had just about everyone in town look at it, and nobody can seem to figure out what the problem is. After reading threads on here all weekend, I have determined that I probably need to replace the ECU. I am having very similar symptoms to the ones listed in this post. I've done some work on my Toyota trucks over the years and have general knowledge and a lot of people to go to for help, but I've never replaced an ECU before. I am hoping that someone can help me with some questions...I haven't been able to find all of the answers by searching...I've tried...very hard.

First - I have the numbers off of the ECU and was able to find a couple around the salvage yards, but do I need to get the original key with it as this post states?

Secondly - I have a key that is stuck in my ignition (it's the wallet key that does not have a remote in it). Will I need to get this out before I can reprogram the ECU, or can I just leave it in there and use the old key open the doors manually from the outside? That's what I have to do already, since the remote doesn't work with a key in the ignition.

Thanks a lot, and I'll be sure to contribute after I get this problem solved!

mitmaks

Don't worry about reprogramming, etc. Just pull your ecu out and send it out to these guys. I just had ours redone and car runs, shifts like new.
http://www.ebay.com/itm/1994-1995-94-95-CAMRY-ES300-ECU-ECM-ENGINE-CONTROL-COMPUTER-REPAIR-89661-33340-/200965883098?pt=Automotive_Services&hash=item2eca8004da&vxp=mtr

Kcm5899

Thanks. Can you give me an idea of what the turnaround was?

mitmaks

I sent it out priority, it got there in 2 days and supposedly they rebuild it in couple of days.
Way i did it is, I asked them if they could check it for me and I just sent it there, I didn't pay for the auction or anything. After it got there I sent them email to let me know when it's done and I'll pay for it etc. On 3rd day with not email response from them I called them and guy picked up and I told him my name and he said it's done. Once I paid their repair fee it was sent to me priority mail and I got it in 2 days.
I guess they don't like to communicate through email so you better call them. However car is fixed now and no issues whatsoever.

Kcm5899

Thank you very much. I'll give them a call and ask some questions. I am wondering if anyone else has had any luck with just purchasing one and putting it in themselves?

mitmaks

Purchasing one would be just as much money if not more and then you'd have to reprogram the key/fob. How do you know your ecu is bad, can you pull codes from it?
When ours went bad car would have hard starts, run real rough for 3-5 seconds and die, it also wouldn't connect to my obdII scan tool.

Kcm5899

Good point. I am not certain that I have a bad ecu, but after reading the symptoms listed by others, I'm pretty certain. The main problem is that it dies randomly while driving. We have ruled out fuel issues and replaced the fuel pump and filter, changed spark plugs, and checked everything to do with the air/fuel mixture. The only code that it throws when running is an 02 sensor. When it dies (will only idle and not rev past 2000 rpms) it will not connect with the OBD scanner. If I leave the car sit for a day or so, it will sometimes run just fine for up to 30 miles, then randomly quit again. I'm actually hoping it's the ecu, but not certain.

mitmaks

I'd check that O2 sensor before messing with ECU, a bad O2 sensor will sometimes cause car to stumble, bad fuel economy, etc.

mitmaks

Actually the issue could be as simple as vacuum leak on your rubber hose that goes to the throttle body or maybe one of the vacuum lines has hole in it. Check for vacuum leaks. If there is one usually that will trigger o2 sensor (cause it senses extra air that comes after MAF sensor)

Kcm5899

I've checked all the vacuum lines for cracks and holes and had the air box, MAF, etc. checked at the local Toyota garage (Lexus is 100 miles away). I talked to the master tech, and he said he doesn't think the 02 sensor would be causing these issues. I have a friend that is an electrical engineer and we are going to tear the ECU apart and see if we can find a problem...I am actually hoping that we can see something wrong.

mitmaks

Looking at it won't help you, I took mine out, looked at it, everything looked great. Without proper diagnostic setup like these guys have, you can't diagnose it. Unless its something obvious like burnt out capacitor, etc.

Kcm5899

Followed the recommendation in the following link and we are symptom free after three days. Still crossing my fingers, but I'm thankful for the information that I found here on Club Lexus and for a friend who knows what he's doing with the soldering iron.

TOTAL BILL: $3.11!


How to fix leaking capacitors