Why won t my LS400 turn on?

This topic contains 31 replies, has 2 voices, and was last updated by garry 8 years, 10 months ago.

18. února 2015 v 1:31 #655596
Účastník

Hi, just got a beat up 96 LS400 and was doing some work on it today. Thought it best practice to disconnect the negative battery terminal while I was doing stuff to be safe. After I had finished and reconnected the battery terminal, I got this:

doesn’t crank at all. started this morning fine before I did all this. Tried various methods online for resetting the immobilizer with no luck. It’s worth noting that I don’t have the original key or fob, just one that works in the ignition and doors, not trunk. not sure if I screwed up somewhere or this is supposed to happen and there’s some simple procedure I need to follow.

Zobrazení 15 odpovědí — 1 až 15 (z celkem 31)
18. února 2015 v 2:51 #655602

Boy you are death to Lexus Electrical Systems…. LOL JK… I would begin by testing the battery to ensure you have at least 12.6v (and possibly get a load test)…. They do it free at most auto parts stores… Also ensure that the battery connections are clean and tight…. Best of luck… -Karl

18. února 2015 v 2:59 #655605
Účastník

Hey Karl, yeah I really am a bane to these things. battery reads 12.25v…I also had a neighbor come over and we tried to jump it, no luck. terminals did have some corrosion on them, cleaned with a toothbrush to make sure it had good contact. given i’ve been at this all day I wouldn’t be that surprised to find out it’s kinda low on charge by this point.

18. února 2015 v 3:17 #655607

The MINIMUM a battery should be is 12.6 voltů…. Also, even with a jump, a car alternator is not a good charger…. Modern cars need good voltage to work right, a low battery charge can cause all sorts of problems… Take the battery to a professional charger (auto parts store) and see if it can come back…. at 12.25v that is not good, you may need a new battery…. At lower than 12.6 Volts, this chart shows how charged the battery is… Yours is only 50% charged…. Good luck -Karl

18. února 2015 v 3:29 #655610
Účastník

also checked fuses, only ones that looked suspicious I took pictures of. http://imgur.com/VKqjjLm,CmtTrG9,XhmPSgy,qudwr0Y

18. února 2015 v 3:31 #655612
Účastník

Huh, didn’t know 12.2 was bad. Going to head to advance with a friend and get a new one or at least have the old one tested, old one is an AC delco but looks at least 4 years old. would having the battery at 50% charge affect their testing machine or can it still tell if the battery is good?

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18. února 2015 v 3:33 #655613

Well that fuse is ugly, but still looks like the working part if it is…. Well, still working… The fuse does not look blown… Those fuse assemblies are very prone to shatter easily when they get old and something hits it….. The plastic gets very brittle… Ironically I just picked up a relay pulling tool that works well with those… I got sick of breaking them with normal pliers and/or and killing my hands trying to pull them out… Seriously, get a real charger on that battery and see if that battery comes back… That we KNOW for sure is not within specs as it stands now…. -Karl

18. února 2015 v 3:39 #655615

[quote=”wonderbread” post=128433]Huh, didn’t know 12.2 was bad. Going to head to advance with a friend and get a new one or at least have the old one tested, old one is an AC delco but looks at least 4 years old. would having the battery at 50% charge affect their testing machine or can it still tell if the battery is good?[/quote] Having a 50% charge won’t hurt their machine, but they may be able to tell you it is bad with a quick test… ALso, may take hours to bring it back… (if it can be brought back) Yes, 12.2 is bad… I try to ensure people know that about batteries… Most people think 12v is good and anything above is just gravy… However it is not so… Good luck! -Karl

18. února 2015 v 3:40 #655616

18. února 2015 v 8:08 #655669
Účastník

Alright, I’m gonig to make a long winded post on all that was fucked up underneath the steering wheel and how I thought of looking under there in the first place, but right now I’m tired and relieved it’s working, so I’ll just post this picture, should explain enough of what the problem was.

http://www.avital.com/
goddamn aftermarket alarms Not even Lexus’ fault lol
18. února 2015 v 8:12 #655671
Účastník
also advance said the battery was k, just needed to charge for a bit.
18. února 2015 v 8:13 #655672

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On the plus side… You are getting really intimate with the electrical systems the LEXUS. Glad you got it worked out… All the best! -Karl

20. února 2015 v 3:29 #655821
Účastník

Hey karl, if you’re still monitoring this thread, I’ve got another electrical issue apparently. I’ve had pretty bad random missfires since I got this car (maybe 4-5 days no), had it into a shop today because it was driving me nuts and I couldn’t figure out what it was. Guy says the #4 and 6 injectors are stuck open, and the ECU is sending them a constant open signal or something of the like. Recommended replacing it. Now, I literally just got home and am going to start research now but could you field some questions for me? 1. Will any ECU from a same year LS400 do, or is the situation more complicated than that?
2. was going to ask if I had found the unit underneath the steerig wheel, but a little research and googling the part number on it shows it’s something about mpx body control, whatever that is.

3.are the cheap (well, $65 ) rebuild ebay services like this a good idea?
4. is this is a common issue? I’m going off this thread http://www.clublexus.com/forums/ls400/656360-all-my-crazy-lexus-issues-solved-ecu-leaking-capacitor.html claiming it is. have it pulled now, going to open it up and see if there’s anything obvious.

20. února 2015 v 3:41 #655824
Účastník
Update: confirmed bad cap on the board.

http://imgur.com/dfyR60A current plan is to find an ECU with matching numbers (TOYOTA 89661-50303).Do I need to match the numbers below it as well? (175000-8780 12V, shown in picture).

20. února 2015 v 5:54 #655835

[quote=”wonderbread” post=128642]Hey karl, if you’re still monitoring this thread, I’ve got another electrical issue apparently. I’ve had pretty bad random missfires since I got this car (maybe 4-5 days no), had it into a shop today because it was driving me nuts and I couldn’t figure out what it was. Guy says the #4 and 6 injectors are stuck open, and the ECU is sending them a constant open signal or something of the like. Recommended replacing it. Now, I literally just got home and am going to start research now but could you field some questions for me? 1. Will any ECU from a same year LS400 do, or is the situation more complicated than that?
2. was going to ask if I had found the unit underneath the steerig wheel, but a little research and googling the part number on it shows it’s something about mpx body control, whatever that is. 3.are the cheap (well, $65 ) rebuild ebay services like this a good idea?
4. is this is a common issue? I’m going off this thread http://www.clublexus.com/forums/ls400/656360-all-my-crazy-lexus-issues-solved-ecu-leaking-capacitor.html claiming it is. have it pulled now, going to open it up and see if there’s anything obvious.[/quote] Well it looks like you have confirmed a bad cap. And yes, this was an issue with these (as you have found out) As far as Fuel injectors open all the time… Well the ECU grounds the wire to the Fuel injectors (to activate them)… If the ECU is bad, the ground could be stuck and yes… Fuel injectors on full time… Another ECU from the same year and model should be no problem… The only thing I would be concerned with is the Immobilizer. (I can’t remember how complex these are for this year). But if it does have one and it is not matched to the key then the vehicle won’t start. The Rebuild services might not be a bad idea… I personally have not used any EBAY based re-builders for electronics yet, but if their feedback was good, I might give it a try. I will probably do this for my 1999 Sierra this summer which has a bad ABS module. Lastly, Again, yes, unfortunately this was a common issue. Good luck. -Karl

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20. února 2015 v 6:59 #655841
Účastník

>Another ECU from the same year and model should be no problem… The only thing I would be concerned with is the Immobilizer. (I can’t remember how complex these are for this year). But if it does have one and it is not matched to the key then the vehicle won’t start. Thanks for the warning here. I don’t think it’ll be a problem for one main reason: the car didn’t come with a toyota key when I bought it lol. owner lost the key and is using some off brand spare (that only works on the ignition and doors to make things worse). So if it’s a thing to do with a wireless keyfob, it shouldn’t be an issue. that being said I’m going to do some more research and see if there’s any info on this out there.

Hello, can anyone please tell me what it could be.
My 99 would not start, when I put key in and try to start nothing happen, won’t crank or even turn over sound nothing, after couple of try it just start. It has 105k mile, starter replaced 2 years ago, went to test battery and its good its only 2 year old battery. It doesn’t do it all the time, worst when I let it sit for a day or two, and when it does start it would start right away even when I turn car off. Anyone have any idea? Thanks

anestézie
07-12-13, 09:23 AM
Testovací řidič Lexus
Založen: Jan 2012
Místo: CA
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Since you have already checked the battery voltage, I think the next thing to check would be the battery cable connectors (especially the positive one). They can develop unseen corrosion damage where attached to the cable conductor. This is easy to look at and cheap to fix.
Also, I would verify the voltage — the cigarette lighter is an easy place to do this. Note that there is no voltage here when the key is OFF, unlike most other cars.

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07-12-13, 10:00 AM
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Obdržel 172 To se mi líbí u 130 příspěvků

next time it fails, put your drivers window down and see if you can hear a click out under the hood, and report back..

billydpowe
07-12-13, 10:19 AM
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Batterey terminal clean intact, windows were down didn’t hear anything. I been searching and reading hopefully it’s somthing simple. Any body have any suggestion

anestézie
07-12-13, 11:16 AM
Datum připojení: květen 2010
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Stole this from another thread.
You’re voltage measurements should be the same.
»
Sounds like a fuel problem, but the speedo issue would be too much of a coincidence, so I would suspect an electrical cause. If the car idles, get a meter and measure the battery voltage without any significant loads. It should measure measure between 13.0 and 14.5 volts at idle. Then turn on A/C and headlights; it should measure at least 13.0 volts at idle. The fact that it cranks okay now, but didn’t at first suggests a bad connection from the battery cabling, so you’ll need to look at everything, wriggle cables, etc. and see if anything is suspect. Missing while idling could be very low voltage to the coils—again, caused by battery or poor connections. The fact that it didn’t crank at first would indicate that ecu/tps/MAF, etc. are not the root cause. Any codes? «

07-12-13, 12:00 PM
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If you jump it, does it start right up? Just because the starter was replaced, does not rule it out. What starter was put in? A factory starter or aftermarket? Usually they just click but the two areas are a good battery and that the battery has sufficient juice to actuate the plunger.

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How are the other electrical systems in the car? Windows, lights, radio, door locks all work?

07-12-13, 01:38 PM
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I’ll update this as I’m bring it to Lexus dealer, I know it’s not the starter (oem replace 2 yrs ago) and not battery. I have a feeling it’s the neutral switch or fuel relay. I know I’m going to get rape by dealer but I just need this fix right the first time plus I get a free loaner to abuse will update with fix. In mean time lets see who gets the right diagnose by just giving your best guess. PureDrifter? LScowboy?

Why won t my LS400 turn on?

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