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Posted

Hi,

First time on the forum. Just got 1995 LS400 from Lexus of Marin. 100K miles. Dealer service records every 5k mi since new documented. Car stalls or has really low idle around 300-400 after prolonged freeway driving. It starts up right away after putting it in neutral and drives perfectly fine. I have found postings that suggest it is the ECU. I am wondering if LEXUS is offered a recall or any special program so I don't have to eat the whole bill if it is indeed the ECU which it sounds like it is.

On a side note, I am going to change the plugs, wires, cap, rotor and both coils because I feel the car miss occasionally in idle.

I can live with the problem, but would like the car to run perfectly since everything else works perfectly fine. The dealer gave me 100 mile/30 day "major mechanical" warranty. but I don't think that the Major Mechanical clause includes ECU, or at least the dealership will give me a hard time about it.

Will appreciate any advice.

Yo


Posted

Welcome! :D

I don't think there is a recall. I think that you could probably argue that the ECU is a major mechanical problem. Tell them there is a major safety issue at hand. Bring it back to the dealer and make them change the computer out. The LS doesn't have coils. ;)

:cheers:

Posted

You may haver already read this..but in case you have not...go here: http://us.lexusownersclub.com/forums/index...showtopic=15699

If you have any pull with the dealer at all....point out the fact that the 95's and 96's had this problem and there was a bulletin on the 96's.

Now..if you cannot get any dealer satisfaction...I would buy a rebuilt ECU..the model I listed as the improved model. They are about $400..a far cry from the price of a new one. Prices vary on these rebuilt deals.

Read the symptoms I had carefully...and if you have the same...odds are it is the ECU. Beat up on the dealer...you have nothing to lose.

And if you decide to replace it yourself...we will walk you right through the very simple job that it is to replace the ECU. By the way...the engine miss occasionally is probably a seperate problem...spark plug or wire most likely.

Posted
Hi,

First time on the forum. Just got 1995 LS400 from Lexus of Marin. 100K miles. Dealer service records every 5k mi since new documented.  Car stalls or has really low idle around 300-400 after prolonged freeway driving.  It starts up right away after putting it in neutral and drives perfectly fine.  I have found postings that suggest it is the ECU.  I am wondering if LEXUS is offered a recall or any special program so I don't have to eat the whole bill if it is indeed the ECU which it sounds like it is.

On a side note, I am going to change the plugs, wires, cap, rotor and both coils because I feel the car miss occasionally in idle.

I can live with the problem, but would like the car to run perfectly since everything else works perfectly fine.  The dealer gave me 100 mile/30 day "major mechanical" warranty. but I don't think that the Major Mechanical clause includes ECU, or at least the dealership will give me a hard time about it.

Will appreciate any advice.

Yo

I had the same problem with my 96LS...my dealer here in Columbus OH replace the ECU and the problem was solved....They didn't charge me anything for this service. This was done about a year ago when my LS has about 79K miles on it.....

Posted
Blake19

Just wondering if yours had or has same problem. 

Yo

I have a low idle if my a/c is off, but I can make my low idle happen on demand. I've never had a problem after long hwy runs.... '95 LS400, 247.3k miles

:cheers:

Posted

My theory is that the ECU closes the idle air control down after X amount of constant rpm...possibly programmed that way for the mass air flow sensor to have better signal. A circuit is supposed to open the idle air control back up when returning to lower rpm and that circuit has a problem. Just a theory.

The idle air control valve is a pulse unit. The ECU pulses that unit to fine tune that idle under different loads.

I think the best test was that I had normal cold startup rpm and it would idle down when warmed up. That proved to me the IAC was working. The only time I had the low idle or dying was after the highway cruise....you could drive around town forever and never have a problem. You could take the highway cruise and then (knowing it was going to go a very low rpm or die at idle) hold your foot on the throttle a little and keep it running...smooth as could be. But take your foot off the gas and it would die. Start right back up and do the normal 600 rpm idle until the next highway cruise. Drove me nuts on a trip to Phoenix.

Posted
blake918 Posted Today, 01:39 AM

  Welcome!

I don't think there is a recall. I think that you could probably argue that the ECU is a major mechanical problem. Tell them there is a major safety issue at hand. Bring it back to the dealer and make them change the computer out. The LS doesn't have coils.

actually the LS has 2 coils a primary and secondary coil.

Posted
actually the LS has 2 coils a primary and secondary coil.

You are right; I wasn't thinking properly. :chairshot:

  • 2 weeks later...
Posted
Hi,

First time on the forum. Just got 1995 LS400 from Lexus of Marin. 100K miles. Dealer service records every 5k mi since new documented.  Car stalls or has really low idle around 300-400 after prolonged freeway driving.  It starts up right away after putting it in neutral and drives perfectly fine.  I have found postings that suggest it is the ECU.  I am wondering if LEXUS is offered a recall or any special program so I don't have to eat the whole bill if it is indeed the ECU which it sounds like it is.

On a side note, I am going to change the plugs, wires, cap, rotor and both coils because I feel the car miss occasionally in idle.

I can live with the problem, but would like the car to run perfectly since everything else works perfectly fine.  The dealer gave me 100 mile/30 day "major mechanical" warranty. but I don't think that the Major Mechanical clause includes ECU, or at least the dealership will give me a hard time about it.

Will appreciate any advice.

Yo

Quite likely excessive carbon deposit inside the throttle body. Have the throttle body cleaned well so there is good air clearance gap for idle air intake even when valve flap is fully closed . Just went through this myself on my 94 LS400. Enough carbon deposit on the valve disk chokes off the air clearance. So after a long drive when idle control is not opening the valve for you since you are no longer "cold", the engine chokes for air and dies when you take your foot off the accelerator. This should perhaps be covered under your 30 day mechanical warranty. It will only get worse over time as the deposits continue to build up.

My 2 cents! Hope it helps.

Posted

my moms old 1987 MB 300E had something similar in I think it was 1995, I remember because I had just got my license and the stupid car died on me a few times.

it was a part called the "fuel distributor", dunno if lexus has something similar, but if it does, maybe check that part?!?

it would just die randomly, especially after getting off the highway.

Has to be a fuel sender problem or a computer problem

Posted

Thank you all,

Took it to Lexus of Marin. Got great service. They identified it as the ECU problem which there is a service bulletin out for. They gave me a loaner for a week (2005RX). I am waiting right now. Please forgive my smart mouthed brother. He's quite young.

Yo Yo Yo

Posted

Please give us the part number of the new ECU they are putting in. It shoudl be listed on your invoice. Also let us know if they are charging you full bore or what. Thanks.

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