95/96 Ls400 Low Idle, Engine Dies And Jerking Thre

[95 ls400]

I have the same problem with my '95. It is a California car originally. It has 32k on it and now resides in Chicago. I bought it wholesale, so I don't think I have any recourse with Lexus. Here are a couple of questions I have:

1) Has anyone run a 49 state ECU in a California car for an extended period of time (I know its been tried for a couple of days without issue)? Does anyone have an educated guess as to whether it will cause any long term problems?

2) Does anyone have detailed instructions on the R&I of the glove box and ECU? I'm not the handiest guy, so maybe I shouldn't attempt it, but any instructions would be great.

3) Does anyone have a good way to search wrecking yards besides www.car-part.com ? I have not been able to find a 49 state ECU with the new part number.

By the way, the reason that I want to replace the current Cali ECU with a 49 state ECU: I had a '95 LS before this one that had 150K on the clock. It had the same stall issue with 2 differences:

1) It only stalled below ~25 degrees f.

2) The engine seemed to have better throttle response than my new one.

My impression is that the difference in throttle response is a tuning/ECU issue as opposed to any maintanence issue. I'd like to get an updated/reflashed 49 state ECU for my present car.

Any wisdom on this is appreciated. Thanks for starting this thread in the first place!

[95LS400Bob]

Bob, well, it finally happened to me.  I was driving a long 3 hours trip from Austin to Houston on my 95 LS and when I got off ramp, the engine just quit like you described.  I never experienced this problem before, maybe because, I just guess here, that I had always shifted to the 3rd gear to slow down the car and therefore accidentally ramping up the rpm - avoiding the ECU problem?!

This situation is quite dangerous that I think Lexus should do a recall on it.  I will attempt to talk to Lexus dealership this week to see if they can fix it free for me.  If not, I may have to send a letter to Lexus regional or national customer care general manager.  Can you imagine how many senior drivers would handle this situation without going panic and causing accidents?

Again, you are doing a great service for all of us here!  Thanks mucho!

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The first time mine did it was at a stoplight. I thought it was just a freak deal. The next time it happened was when I was turning into a parking lot. The extra force of the power steering stalled the already low idle. Had that been my wife driving...she would have missed the driveway and gone in the ditch with no power steering. So...yes it is very dangerous. Why I went to such lengths to find it.

[95LS400Bob]

I have the same problem with my '95. It is a California car originally. It has 32k on it and now resides in Chicago. I bought it wholesale, so I don't think I have any recourse with Lexus. Here are a couple of questions I have:

1) Has anyone run a 49 state ECU in a California car for an extended period of time (I know its been tried for a couple of days without issue)? Does anyone have an educated guess as to whether it will cause any long term problems?

2) Does anyone have detailed instructions on the R&I of the glove box and ECU? I'm not the handiest guy, so maybe I shouldn't attempt it, but any instructions would be great.

3) Does anyone have a good way to search wrecking yards besides www.car-part.com ? I have not been able to find a 49 state ECU with the new part number.

By the way, the reason that I want to replace the current Cali ECU with a 49 state ECU: I had a '95 LS before this one that had 150K on the clock. It had the same stall issue with 2 differences:

1) It only stalled below ~25 degrees f.

2) The engine seemed to have better throttle response than my new one.

My impression is that the difference in throttle response is a tuning/ECU issue as opposed to any maintanence issue. I'd like to get an updated/reflashed 49 state ECU for my present car.

Any wisdom on this is appreciated. Thanks for starting this thread in the first place!

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1. I went from the Califonia Ecu to a 49 state ECU about three months ago. The only issue I can see is more power. The wife commented the car is "spunkier." I see no problems at all and do not expect any.

2. There is not a lot to detail. Just remove the underpanel (2 screws and it snaps out.) Then remove the glovebox. Look up in there and you will see it. It's the one with all the plug ins. In fact..you can read the number of the ECU without remving it. Label is on the side of it. But you gotta near stand on your head.

3. I think at this point I would opt to find a rebuilt ECU with the latest flash. That truck electric place had the best deal on them. Search my threads...I know I mentioned that place and the part number.

[95 ls400]

Thanks Bob! I'll give that place in Florida a call.

[bicol-ini]

got that number or web site for the florida place? pls let the forum knows

[95 ls400]

got that number or web site for the florida place? pls let the forum knows

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800-257-3395

[nc211]

I have a 95 with 94k miles, had the "jerking" issue happen shortly after I bought it with 85k miles. Thanks to these forums, I was able to understand what it was. And thanks to that "90 day / 3000 mile window warranty" the dealership put on it, I was able to get it fixed for free. But, it took some serious words and few legal terms to get them to do it. The ECU units in most of the 95 and 96 models have this flaw. Once you have it fixed, it's fixed for good. No jerking, no stalling and smoother shifting. The old ecu has a programming flaw that drops the fuel flow too quickly, causing the engine to suffer "off-throttle shock".

Now if I could just wack that darn vibration issue that everyone else has too! LOL. :chairshot:

I got new motor mounts, tranny mounts, ball joints, the standard issue stuff already.

[bicol-ini]

hello, 95ls hows the progress on your ecm, any updates from the florida guy

[95 ls400]

hello, 95ls hows the progress on your ecm, any updates from the florida guy

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I called the Florida guy. They want $325 to reprogram my existing ECU. Since I'm not really driving it on long trips right now, and since I'm the only driver, I'm holding off for now. I'd really like to find a used one. If anyone has any leads on where to find one, that would be great. If I don't find anything after a month or so, I will probably send my ECU off to FLA for a vacation. However, I'm not really excited about being without a car for a couple of days, nor am I looking forward to spending $325 to upgrade an old part.

[srgilbert]

I purcahsed a used one for under $150 on car-part.com which came with warranty. This ECU change made a dramatic improvement in my 95 LS.

hello, 95ls hows the progress on your ecm, any updates from the florida guy

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I called the Florida guy. They want $325 to reprogram my existing ECU. Since I'm not really driving it on long trips right now, and since I'm the only driver, I'm holding off for now. I'd really like to find a used one. If anyone has any leads on where to find one, that would be great. If I don't find anything after a month or so, I will probably send my ECU off to FLA for a vacation. However, I'm not really excited about being without a car for a couple of days, nor am I looking forward to spending $325 to upgrade an old part.

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[95LS400Bob]

Just so you know. $325 was the lowest price I found for a rebuilt..anywhere out of the remanufacturers. Generally they ship you a rebuilt and you ship your core back for credit. Used ones are tough and maybe you get another one doing the same thing. Remember it's a problem with a lot of 95's.

Most quotes were $500-$600.

[95 ls400]

Just a little update:

I took mine on a ~3 hour trip this weekend. I noticed that if I turned the A/C control on and off, it seemed to "reset" the idle. In other words, I didn't have to keep the A/C on in order to hold idle. Turning the A/C on and off seemed to have the same effect as turning the car on and off, and offers a temporary fix for this annoying problem.

Has anyone else noticed this?

[95LS400Bob]

Not sure if this is the same thing...but....one of the guys mentioned that after a highway cruise and he knew he was going to come to a stop...he would turn on the a/c and that would keep the motor from dying when he stopped.

On my deal (read all the posts I did in this thread) when we bought the car and drove it in from Las Vegas....it never died. Later we attributed this to the a/c was on the whole trip.

[Speedy J]

Bob,

I am not the guy that mentioned to do that trick to prevend the car from dying but I also do that. Sometimes I even let the engine die "on purpose" by putting the gear in N, so the needle drops to zero. I then immediately ingnite again and put the gear in D to follow my way :))

This I only do on staight roads and low traffic. Coz Steering and breaking becomes tough without electronic help...

Most of the times I indeed switch on A/C to boost up the idle.

Last week I pointed out this thread to my dealer. They already tried to fix the problem but couldnt find anything so the next step would be to step by step replace the mechanical parts which might cause the problem. Now my dealer has ordered a new computer. Since the problem came when they changed my computer for another problem during my warranty period I guess I won't be charged for this new computer (warranty on repairs) . I surely hope the problem will be gone after installing the new ECM. I will let you know my results.

In the mean time, thanks for this sollution-thread!

[95LS400Bob]

Quite a deal isn't it? LOL. We have these wonderful quiet smooth running cars until we take a highway cruise and then they quit at a stop light. Restart and all is normal again. Till the next highway cruise.

Meanwhile you drive around town and all is normal.

Drove me nuts. I had to find it.

For the record...see if you can find out what number is on your present ECU and what number is on the one they replace it with.

And we are all glad we are training your dealer. Instead of throwing parts at it.

[yoichisoma]

Anybody have advice on how to take the ECU out? Ive got the glove box out and the lower bracket nut out but the upper bracket and nut are burried way up there. Help!

Yo

[iatimlee]

Anybody have advice on how to take the ECU out?  Ive got the glove box out and the lower bracket nut out but the upper bracket and nut are burried way up there. Help!

Yo

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Yo,

I just pulled my ECU a few minutes ago. I didn't think to take pictures until after it was too late but you're past that point anyway.

I saw 2 options for removal - remove the 2 phillips head screws from the top of the ECU that hold it to the bracket OR remove the bracket with the ECU and seperate it after removal. I chose the latter because it looked easier. A matter of choice I suppose.

If I remember correctly, you have a Nak just like mine (?). This adds a little extra work over the standard stereo. There is a small aluminum box behind the cd changer that needs to come out to get good access. There is a power plug on one end and a pig tail plug connected to this box that goes intot he back end of the changer. Pull the pig tail straight out - it's sort of like a mini version of an antenna plug. There are two 9mm nuts holding this box in place (one on each side).

After that is removed you will get access to the door control box. Not sure what this box is for. I thought the key fob receiver was in the trunk (?). Anyway it's a small black box mounted to the bracket that holds the ECU in place, but it's the last think blocking access to the bolts. Once you get it out of the way, the last 2 nuts on the ECU/cruise assembly bracket are easy to get to.

FYI - ecudirect.com is not able to upgrade ECU's - only repair them, but they do work with suppliers that can get a tested, working, upgraded model from a donor car. I'm waiting until this afternoon to see if they have a part for me. If not, my ECU is going on Spring Break in sunny West Palm Beach, FL to visit the guys at Auto & Truck Electronics for the software upgrade.

I'll keep you posted. Let us know what your results are too.

Tim

[iatimlee]

I got my ECU back yesterday afternoon from Auto & Truck in FL so I installed right away. After a short 10 mile trip to verify everythign was working fine I was happy with the upgrade and put the rest of the glove box back in place. A few hours later I had to drive to the airport to pick up my wife and after a 30 mile trip at 70 MPH, I came to the exit and when I got to the stop light the engine idled down to 200 RPM, bounced around just a little and then died - exactly like it used to.

The 'off throttle shock' that causes the jerking when letting off the accelerator seemed less but not completely resolved.

Needless to say, I am disapointed. Including shipping I spent just under $400 and I can't tell that they did anything. I specifically stated that the ECU was functioning and was only being sent in for the software upgrade.

I'll pull the throttle body to be sure I don't have something hung up in there, but I can't reason why that would only be an issue after long highway speeds.

Anyone got any comments? I'm lost now.

[nc211]

Could it be a throattle position sensor going bad maybe? Question: when you were on the highway, did you engage the cruise control? I know the TSB issued on this matter calls for the cruise control ECU to be replace as well. Along with the spark plugs. Don't why they needed to be included, but they are. I'm wondering if this highway cruise=stalling engine isn't related to a faulty code being sent from the cruise ecu to the main, like they can't talk to eachother properly.

[maxed_out]

lee, hey dont feel so bad. Have to agree with nc211. Go for throttle position sensor. Mine did something similiar and it was the tps.

Maybe all you need is to have it adjusted?????

[95LS400Bob]

I got my ECU back yesterday afternoon from Auto & Truck in FL so I installed right away. After a short 10 mile trip to verify everythign was working fine I was happy with the upgrade and put the rest of the glove box back in place. A few hours later I had to drive to the airport to pick up my wife and after a 30 mile trip at 70 MPH, I came to the exit and when I got to the stop light the engine idled down to 200 RPM, bounced around just a little and then died - exactly like it used to.

The 'off throttle shock' that causes the jerking when letting off the accelerator seemed less but not completely resolved.

Needless to say, I am disapointed. Including shipping I spent just under $400 and I can't tell that they did anything. I specifically stated that the ECU was functioning and was only being sent in for the software upgrade.

I'll pull the throttle body to be sure I don't have something hung up in there, but I can't reason why that would only be an issue after long highway speeds.

Anyone got any comments? I'm lost now.

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[/quote

Call them and tell them the problem. Refer them to this thread. It is an ECU issue. Been there and done that. Dirty throttle bodys and throttle position sensors don't know a drive around town form a 70 mile trip. Something about the ECU does.

Make sure you can answer yes to the following questions:

1. I can drive around town all day..day after day and never have and idling issue or dying issue.

2. If I take a highway cruise at 60 mph or higher...regardless of whether I use the cruise control or not...30 minutes of continuing at speed...then when I come to stop...the engine will have extreme low idle (200 rpm) and then die. It restart immediately and idles normally forever....until I take that next highway cruise.

That said...I believe it is not a software issue..but rather a hardware issue...as some people have ECU's identical numbers....one guy has a problem..the other guy does not.

For $400....you should have received a rebuilt and tested ECU....like the other people that ordered from them.

Read all of my posts as I hunted this ecu thing down. You will find where I borrowed an ECU from a fellow member to test the problem and it cured it. I never sent him the ECU back...I bought it from him and it is still in the car today with no problems.

List the number on your ECU.

[iatimlee]

I'm including a copy of the letter (minus my personal info, of course) that I sent with my ECU when it went to FL. I dealt with Alan there and he seemed to be aware of the problem and I mentioned to him that I had been referred to them by this thread. It sounded to me like regardless of what the ECU is sent to them for, the hardware is verified first and then any program updating is performed. I have always had a problem with the argument that this fix was software related - maybe I'm adding that, but I really thought I saw somewhere that the upgrade was strictly a programming upgrade. It seems to me that if it's softwaer it would be more repeatable and should have been there from day 1.

I do have the exact symptoms you describe. The car runs like a champ until I get out on the highway and hit 65+MPH for any distance - then it idles down to 150 to 300RPM and dies, either on the offramp or at the stoplight. As soon as I put it in neutral and restart it idles great again - could this be the TPS resetting itself to a home position? The TPS is almost certainly in a different position at 60MPH vs. 35MPH, right? I also have the off throttle shock problem where the car jerks and kicks when you let off the throttle anywhere between 40 and 65. I do use the cruise and I've had problems off and on where the cruise resume does not work. I have to reset it after I've hit the brakes, but not every time - maybe 40 or 50% of the time it doesn't work. Does ATE do cruise rebuilds? Anyone got a source for those? I haven't done plugs yet but I suppose it's time. I've put 50,000 on the car as it's second owner without doing them yet. I bought it from the Lexus dealership that did all the maintenance (I've even got their records) so I'll see when the last set were installed. I've got a few things to check, I suppose. I was just hoping the ECU was the magic bullet. Are you thinking I still have a bad ECU?

My original ECU was the 89661-50221. I specifically asked that it be upgraded to the newer Lexus programming in 89661-50224. I'm going to call Alan back at ATE and see what can be done. Thanks for the quick replies. If I have to pull my ECU out again (and it looks like I will), I'll take pictures and try to create a DIY tutorial. Sounds like there is a need.

ECU_work_letter.doc

[flash213]

I just returned from buying my Californian 95 LS400 and have expeienced the same problem, coming off the interstate and dying on the offramp. Really dangerous! Im really interested in reading any updates from owners switching from the Californian ECM to the 49 state ECM. Any problems poped up? Improving the performance would be an added bonus. A serious thanks goes to all that have helped on this thread. I will follow up with my experience soon.

[95LS400Bob]

You have the exact symptoms I did. And I replaced my California ecu with a 89661-50221 and it solved the problem. That tells me something is wrong with your 89661-50221 ECU.

The following is just a guess. Since the car idles normally until that highway cruise, my guess is that the ECU (for whatever reason) closes down the Idle air control valve to nearly closed after X amount of time at X amount of rpm/mph. The ECU is supposed to signal the idle air control valve to reopen on decleration or stopping after that cruise and it is just not doing it. This could be a certain electrical section in the ECU itself that malfunctions.

I do know the idle air control valve has to be pulsed many,many times by the ecu to open or close. It's a pulse motor. I had mine off and even drilled it and took it apart...thinking that had to be the problem.

But when I got to thinking about it....if the idle air control was not working right or hanging up..then why did I have a perfect fast idle on cold start and perfect idling all other times except for that highway cruise dealio?

I had thought up a test to catch the idle control in the act (closed after the highway cruise) but forgot how I was going to do it.

I heard some guys simply turned on their a/c system when they knew they were coming to a stop and that got them by. This might make sense as when we bought the car and drove it 500 miles home, it never died. It was summer throught the desert and we had a/c on all the time.

The ECU knows the a/c is on and it opens the Idle air control valve to compensate the load to keep the idle rpm the same.

[95LS400Bob]

I just returned from buying my Californian 95 LS400 and have expeienced the same problem, coming off the interstate and dying on the offramp. Really dangerous! Im really interested in reading any updates from owners switching from the Californian ECM to the 49 state ECM. Any problems poped up? Improving the performance would be an added bonus. A serious thanks goes to all that have helped on this thread. I will follow up with my experience soon.

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I'm probably the only nut that tried it. :D Worked great for us...more power for sure and still passes smog no sweat. Wife drives it every day and she was the one who commented "more power".