93ls400walt

Engine Ecu Rebuilder

Recommended Posts

I have a 93ls that has 2 leaking caps on the circuit board. With the car running smooth then surging back and forth, idle way up then idle way down. stalling at stop lights. The later will run perfect.

So I have read some stories of bad service with ECU rebuilders. Have any of you had good results with an ECU repair? And if so can you give a name and contact info. Or name and city where they are located.

Thanks, Walt

Share this post


Link to post
Share on other sites
I have a 93ls that has 2 leaking caps on the circuit board. With the car running smooth then surging back and forth, idle way up then idle way down. stalling at stop lights. The later will run perfect.

So I have read some stories of bad service with ECU rebuilders. Have any of you had good results with an ECU repair? And if so can you give a name and contact info. Or name and city where they are located.

Thanks, Walt

Definitely can be repaired. Repairability will depend on condition of the board. Any decent electronics shop should be able to effect repairs. Just make sure the caps aren't noname generic from china. If the board is damaged it will have to be replaced. Obviously can't rec for cal.

Share this post


Link to post
Share on other sites

Thanks for your input.

I found 2 places listed on Club Lexus via Google search. Foreign auto computer and Auto&Truck Electronics, both in Florida. FAC wants $250.00 and A&T elect. will do them for $99.00 but had 2 very negative reviews for non ECU car electronic repairs.

Share this post


Link to post
Share on other sites
I have a 93ls that has 2 leaking caps on the circuit board. With the car running smooth then surging back and forth, idle way up then idle way down. stalling at stop lights. The later will run perfect.

So I have read some stories of bad service with ECU rebuilders. Have any of you had good results with an ECU repair? And if so can you give a name and contact info. Or name and city where they are located.

Thanks, Walt

Hey Walt..may I ask how you know you have 2 leaking caps?

Share this post


Link to post
Share on other sites

I opened the ECU case. It has 2 circuit boards in it facing each other with all of the caps and transistors inward. One of the boards had to be unscrewed and freed up ( stuck to the case ) and raised up to look between them. I saw corrosion on one cap and the second had leaked onto the board about the area of a nickle. Staining the circuit board dark.

When I first removed the 2 metal covers from the ecu exposing all of the soldered connections. Everything look pristine. But I remembered from other post the the caps were sometimes at fault. So I gingerly removed the screws from one board and had to pry around the edge to loosen it.

Share this post


Link to post
Share on other sites

I opened the ECU case. It has 2 circuit boards in it facing each other with all of the caps and transistors inward. One of the boards had to be unscrewed and freed up ( stuck to the case ) and raised up to look between them. I saw corrosion on one cap and the second had leaked onto the board about the area of a nickle. Staining the circuit board dark.

When I first removed the 2 metal covers from the ecu exposing all of the soldered connections. Everything look pristine. But I remembered from other post the the caps were sometimes at fault. So I gingerly removed the screws from one board and had to pry around the edge to loosen it.

Hmmm. Any focused, close-up pics of the offending board? I would like to take a look.

Share this post


Link to post
Share on other sites
Sorry, no pics. Sealed it back up. going to send it to ECU TOGO in Houston for repair.

Well if you are handy with a soldering iron you could probably replace the caps yourself. I presume they are marked with a capacitance in micro farads and a DC working voltage. Depending on what their role is in the circuit they could be slightly more exotic low ESR capacitors but they maybe just fairly typical electrolytic aluminum caps. If the board is conformally coated (a waterproof coating) then you need to restore that to the areas worked on. I would just spread some silicone/RTV over the areas you broke through the coating to restore the waterproofing.

Its no sure thing even with the staining you mention that this has anything to do with the problems with your engine running. Can these guys even test an ecu? I suspect that takes a fairly elaborate test bed.

Share this post


Link to post
Share on other sites

Well I sent my ECU to ECM-TOGO in Houston. They tried to repair but said it did not test out in the post repair testing. So on to Ebay, I bought a used ecu and installed it. The car runs like crazy ( good ) I have had the ls for 5 years and it has never ran so well. The cel codes 41 and 47 are gone. Which 47 is for sub throttle position sensor. Which my car does not have. Also the O/D light stopped flashing cel code. The trans does not skip 2nd anymore. And my tach which worked on and off now seems to be working all of the time. ( I know, could that be! )

Cured symptons;

skipping 2nd gear from a stop

inability to press on the gas more that very, very lightly without the rpm dropping and car slowing down

Flashing O/D light for vehicle speed sensor

surging of rpm 200 to2000 with constant pedal position on

dying at idle

strong gas smell

14mpg in city ( hopefully, still working on new tank of gas )

ECM-togo

I was treated very well in my dealings with ECM-togo. The staff was great,they waived the $45 fee for diagnostics, which would of been applied to the $275.00 rebuild fee if my ECM was rebuilt and working. In Fact they said they cleaned the circuit boards and replaced the caps even though they thought the board was shot. Put it in the test car ( they have an ls ) But it did not work 100%. They only charged me for return shipping.

Share this post


Link to post
Share on other sites

It's just amazing how many problems a bad ECM can cause. My '96 also had a bad ECM which I replaced for $200 from a low miles wrecked LS. I had low idle, high idle, would flood every hot start attempt, ran horrible hot, P0115 ECT circuit malfunction, gas smell, smoke from exhaust, etc... and the new ECM cleared them all right up.

I have began to think ECM's are wear items on these cars and tend to go out with higher mileage cars? I'd guess your car is over 200k with a bad ECM? Mine went out just over 200k. The guy I bought the ECM from say's he see's alot of 94 and 96 ECM's go bad that have high mileage. Funny how an electronic part can have a mileage/use based life.

Share this post


Link to post
Share on other sites

Wow maybe I should check out my ecm. I have an intermitant unburnt fuel smell, low idle, and weird smelling smokey exhaust. And guess what! I am right under 200K miles. I have a guy with a parts car that I could probably get an ecm from. Will a '94 ecm work in a '93? The two years are practicly identicle. I doubt if a 90-92 would work.

Share this post


Link to post
Share on other sites

I wouldn't bother swapping a different year ECM in. I've heard similar year ECM's will work with similar year cars but you may have a CEL. Do you know someone who has a '93 LS that you can swap the ECM for a miles to troubleshoot?

Not to hijack the thread, I would clean the throttle body first if you have not already. Does your car hesitate when you rev off of idle? Do you have a CEL now, maybe a bad o2 sensor causing rich run condition. Also think about your ECT sensor for the ECM. If you car doesn't think it is warming up it will run rich, but that usually has a high idle associated with it.

Share this post


Link to post
Share on other sites

93 and 94 are switchable. What you need to do is pull the ECM out and see what model number you have. And replace with the exact one. As there are federal and california models ( different smog stuff ). And with or without traction control. So get the number!

As for ECM-to-go, all the praise that I posted, I take back. It has been over three weeks and they still have not returned my ECM.

My ls is still running GREAT. The tach and speedo are again intermittent . I did not think that the new ECM really fixed this. Just a fluke.

If I ever get it back I'll open it up and get some pics to post.

Oh, and my ls has 130,000 miles. It spent most of it life, except the past 5 years, on the Atlantic coast of Florida. If the heat and humidity/salt air had anything to do with it.

Share this post


Link to post
Share on other sites
I have began to think ECM's are wear items ........ Funny how an electronic part can have a mileage/use based life.

That isn't the typical failure mode for electronics. They can be prone to infant failure mode due to manufacturing defects or faulty components but once they are "proved in" (i.e. work for a couple years) then the failure rate would be just random failure of components which is a statistical event. I’m sure Lexus engineers have designed the ECU with extraordinarily high MTBF so those random failures would be quite rare. The only exception would be these leaking electrolytic capacitors some speak of. That is a premature failure mode but it would be more due to age and heat than miles driven.

So I wouldn't plan on swapping an ECU based on an odometer reading. You'd need other factors pointing you there to justify such a big (and expensive) swap.

Share this post


Link to post
Share on other sites
btw where is the ecm located and how easy is it to swap? I heard its in the right floor area of the passanger capartment is that accurate at all?

It is under the panel beneath the glove box. The engine ECM & the ECT module are both located here... just took mine out yesterday....I opened it up & both boards look good...my car has 268k miles on it..

Share this post


Link to post
Share on other sites

93ls400walt,

I had all the same symtoms that you had but on a 1992 LS400.

Hard to start - low battery, severe strain on battery to start, it was showing around 7 volts

I know alternator & battery were good.

Sputtering when stepping on gas

No 2nd gear at times

Severe electrical drain on headlights,dome lights,

Dashboard flickering

Osolating idle between 1,500 to 2,000 rpm at startup

Radio cuts out when I step on brake - radio back on when I release brake

Antilock brake light on -

Low radiator light on, low battery light on, brake light on, low engine oil light on occasionally

All this sounded ECU related......wasnt sure so I decided to pull it & examine

Procedure:

Cleaned battery posts & reconnected; pulled fuse to clear all error codes ( dont know what they were if there was any but I didnt care what they were as there was many things going wrong ); pull the 4 plugs out of the ECM module & examined the guts of ECM Module....it looked fine( no corrosion or leaking capacitors ), reinstalled & reconnected all 4 plugs.....

Results: runs great; at this point I have not had to buy a used ECM fro ECM ToGo.....

Hopefully, my fix has work, hope it is not temporary

Share this post


Link to post
Share on other sites

Spoke too soon...all of my previous problems are reappearing.......

Now I am starting to think it is an alternator problem.....will have it checked out this weekend....with load & no load.....

I will advise on outcome...

Share this post


Link to post
Share on other sites

Hey fiveofakind,

to me it sounds like you may have 3 different issues going on.

1) battery drain/low lights is most likely related to old battery not charging or the alternator going bad. If your handy you can replace the brushes in the alternator for around $20.00. Ordered mine from Park Place Lexus-Plano Texas. Autozone or equivalent can check your charging system.

2) radio cutting out with the brakes may be related to the drivers side trunk hinge wires. Pull the black trim and trace the wires back toward the window. To and past the fixed bend points for the harness. Look for cracked or broken wires. Splice in new wire to any suspicious areas.

3) sputtering, no 2nd gear and idle issue can be many things. But I had gone through a lot of Seafoam, throttle body cleaning, new TPS, plugs, wires, caps, rotors, coils, new vac. hoses. The car ran better with all of this. But never fixed my idle, 2nd gear or lack of acceleration. The " new " ECM however did.

Good luck

Share this post


Link to post
Share on other sites

I bought a used ECM. Said it came from a wrecked ls. for $160.00. ECM-TO-GO say they will test your ECM and replace the bad parts for

$275.00. They told me mine had a pretty bad circuit board. But they rebuilt it and tested it on a ls. And that it still malfunctioned. Then offered to sell me an in-stock rebuilt one for $495.00.

I found one on e-bay and called them to give them a credit card number to pay for shipping my old one back. That was a month ago. I am still waiting. My take on this is everyones ECM is is unrepairable. You buy " one we have in stock " for twice the price. They keep your old one and sell it to someone else.

Share this post


Link to post
Share on other sites

I had the similar problem, the idle issues and the acceleration, all initially was the ECM as the target, but after much trouble shooting, I found out that the below Part, which is directly propotional to the Acceleration and idle issues. P/N - 89452-33010 - Throttle Position Sensor, this connects to the Traction Throttle Valve Motor. Replaced the faulty one, It has not been better, all issues resolved and perfectly working.

post-21708-1267187078_thumb.jpg

post-21708-1267187094_thumb.jpg

Share this post


Link to post
Share on other sites

man777,

The throttle position may solve the oscillating idle, & sputtering problem but will not solve my electrical issues going on.

I will be replacing my alternator & battery this weekend & hope this clears up my problems... I will then look into this throttle position sensor in the factory shop manual....

Doing the labor myself will save $$$$......alternator about $ 120 & battery $ 50-75....then I can eliminate these 2 parts out of the equation.....

The car completely die on the way home...had to have it towed....battery was spent with only 8 volts left in it....

I will advise...

Share this post


Link to post
Share on other sites

You are right, but I had mine kinda of same issue going dead and then a sudden recovery after a long break. Do some tests to find out if the alternator is dead totally, I presume The whole alternator cannot be dead- the trigger are due to few parts which are critical in its function, most of them can be replaced, example such as the solenoids, Alternator brushes, Rectifier.Condenser And if were you I would not replace the stuff, have it rebuilt, as the new one cost 890/- and that is just the rotor assy, then you need to add on all of the above I have listed which will run above 1.5k or you may have to get one from the salvage yard, lucky if you get one good conditioned one. Good luck

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...