beltz97

hi - have shifting problems ...transmission was working fine until this happened. the shifting problem seen now is it doesn't go into the top O/D gear at highway speed and intermittently it sticks in lower gear or loses gear completely (like i'm in neutral)

check engine is on and "o/d light flashing" are flashing.

diagnosis was done at local repair shop and vehicle speed sensor replaced but it didn't solve the problem. now the new codes are
PO520
PO700

and they recommend replacing the ECM (w/ a reman'd one)

how have others faired w/ reman'd ECM's vs the OEM ECM?

worried once i replace this, it will just go on and on w/ something else

mmlex1987

I would have a lexus/toyota tech diagnos and get a second opinion.

fantomZ

I'm new here, working on a friends ES300 but my question is related to this post and rather than making a new thread I figured I'd ask here. This may help the OP as well.

I am in need of replacing the ECM in a 99 es300 but was told that all of the theft immobilization parts would need to be switched out as well by the guy at the salvage yard. Is this true? Is there a way around it?

If I just switch out the ECM with another good known unit, matching #'s, it still won't work because of the immobilizer?

Thanks and I'm not trying to threadjack

-Adam

fantomZ

Posting follow up for future reference since I wasn't able to find much helpful information about this specific issue.

Replacing ECM (ECU) on 1999 Lexus ES300 with a salvage ECM (ECU)

When purchasing a salvage computer to replace a non-working or malfunctioning unit you must match the numbers on the computer. 89661-your#, and you must obtain the key that came from the car the the computer came out of. I had to call about 10 different salvage yards over the US to find one that had both. You have to have the matching key in order to re-program the key that fits your ignition switch. This means master key, not valet key.

Once you have received the computer and matching key, unhook the battery, replace the ECM, hook up the battery and do the following procedure. (The following info copied from another thread on CL, combining for more comprehensive computer replacement guide.)

Key Programming
1. Insert an already programmed master key into the ignition(The one you got with the salvage computer). Do not turn.
2. Press and release the gas pedal 5 times.
3.. Press and release the brake pedal 6 times.
4. Remove the key from the ignition.
5. Insert the new key (really your old key, the one that goes with your doors and ignition switch) you want to program into the ignition.
6. Press and release the gas pedal one time.
7. Wait 1 minute. The security light will be blinking for this one minute. When it stops blinking your key is programmed. To end programming step on brake one time.

NOTE: Look for your security light. This light will guide you during the programming procedure. The security light will go off at Step 1. It will remain off until Step 6. The security light will come on and start to blink after Step 6 until the key is programmed. If the security light comes on after Step 4 STOP the procedure and start over again.
If you perform this procedure too slowly your car will not go into programming mode. If you can not get your car to go into programming mode make sure you are using a master key and not a valet key. If you have a master key then you will probably need to perform this procedure more quickly.

After this, your key should have received the programming from the key that was originally with the new (salvage) computer and will start the vehicle.

Hope this helps someone else in the future, this was about a 2 month information hunt/PITA to fix the issue that we were having.

-Adam

pookie1090

What are some symptoms of the ECM going bad!

sam12345

iTrader: (1)

How do you put the master key that came with the ECM into your ignition switch when the key is cut for a different switch?

yeskay

why can't the original ecm be sent out and get the issues fixed .

Rigo

I just bought a used/ salvaged ECM. From what I'm seeing on this post.... Means this used ECM won't work on my car at all?! Can't I just get it programmed, as in "its my ecm" but I lost my keys, so I need to replace them, type of thing? I wonder if that made sense.

mitmaks

Yes you can. Send your oem ecu/ecm to this guy and he will fix it for you.
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

Fixemall

Incredible. We did send. He did fix it.

Our particular 1994 ES 300 has had some after-accident rebuilding done (well done, but you can tell when you know what to look for - tail light assembly still has the yellow numbers in crayon on it, freshly dough-boyed seams on the trunk pan, etc.) but has only 80k miles on it and I am frankly looking forward to another decade of service from it... If I can get this problem fixed.

The timing belt job on this was... ahem... epic? Who designed it that way? Small price to pay for an expertly (in all other ways) engineered vehicle. That job (and yes, did the water pump at the same time) is complete.

Here's what happened that created the current problem.

The factory battery negative let go during operation. I installed a new cable and terminal end, and the car drove fine for a few days... but then began to 'not lock up' on the transmission. It would move forward at about half the speed the engine was running. Did some research, learned about the transmission relays, and that they might be causing this problem.

I checked the two shift relays in the transmission and they operate when supplied current. I was told by some of the genius Lexus/Toyota mechanics out here that 'they sometimes work intermittently' and there that there is truly no definitive test for them. I don't know Lexus that well, but I know relays, and that made little sense to me.

I presumed that the lost ground during operation might have spiked the ECM.

I cycled the battery twice, and the problems in shifting would cease temporarily (for a day or two) which also lead me to question the efficacy of the ECM. NO ONE IN WISCONSIN can check an ECM from 1994 anymore to see if it 'throws codes'. (I do all of this work with a continuity tester, a floor jack, and a standard wrench set in my garage).

So I removed the ECM, sent it in, (to the gentlemen you suggested), they found the problem and fixed it in the ECM.

Now I am worried that the theft protection on the car will kick in after I re-install the ECM.
Is this a justified worry as the ignition key is not coded? Is there a procedure I should follow?

I am a general mechanic that works on all types of cars... I just happen to be quite fond of the Lexus line and hate to get rid of it over a shifting problem.

mitmaks

I wouldn't think that theft protection would kick in as this is your OEM ECU. Our 96es300 has some theft protection/factory alarm (same one you're probably talking about) and once I put in ECU there were no alarms,etc whatsoever. Car has been running great ever since.

Fixemall

Thanks mitmaks... someone telling me not to worry is better than nothing. Today is the day (Saturday) for the re-install - I'll let you all know if the operation solved the problem.

I do know my wife REALLY wants her Lexus back.

Fixemall

Its installed.

It works!

I now plan to wait a few days (the car gets daily use) to ensure that the 'lack of shifting lock-up' problem is also a part of history, but the test drive today was problem-free, and she 'rips' like she used to.

Thanks to all here for the advice/help. She rides!

I would like to add my endorsement for the ECM rebuilder outfit to that already posted by mitmaks as well: They do excellent work, at a good price.

BadES300

Hello! New here and have an absolutely CURSED 2000 ES300 that's incredibly well maintained but nothing BUT problematic. I need a new ECM.

Can anyone give me the contact info (phone number doesn't work from the image above) for the person/company that rebuilt your ECM's?

BadES300

Do you have any more info on this guy? That phone number doesn't work. I'm in desperate need of a new computer/computer rebuild and would be SUPER grateful if I could get an email address or new phone number if at all possible.

THANKS!