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First I'd like to say that I did a search and found plenty of speedometer problem threads but I could not find one with a resolution to my issue.
I just bought a LS400 ('99) at a dealer with 141k and I paid under 3k for it. It is in fine shape and runs beautifully. I needed a car to commute to work with (100 mile round trip per day M-F) and knowing how dependable these cars are I decided to buy this one.
The only major issue I have found so far is the speedo does not read correctly. The tach works fine, the odometer works fine and the car shifts beautifully. When I first start to drive the needle doesn't move (it is not stuck from what I can tell) and only once I get up to 20 mph or so it starts to rise. At 40 mph on gauge I am actually driving at 60 mph according to my GPS.
My first thought was the input / output speed sensors on the trans (I have replaced these before on my Hyundai XG350L so i am aware of when to replace these) but I am not seeing any telltail signs that the sensors should be replaced.
If I somehow missed a thread here on this exact issue then please link it if you don't mind. Otherwise; any ideas?
So the odometer works fine. It simply means that the speed signal from the upstream is OK. You need to fix the speedometer alone.
One more thing you should know is that the VVT engine models do not get the speed signal from the transmission. Those get it from the ABS/TRC/VSC computer as is shown below. One tire rotation generates 48 pulses and the pulses are processed by the ABS/TRC/VSC computer and sent to both the odometer and speedometer. The process is to remove the noise and to get the average and divide by 12. So the cluster unit receives 4 pulses when the tire fully rotates 1.
So the odometer works fine. It simply means that the speed signal from the upstream is OK. You need to fix the speedometer alone.
One more thing you should know is that the VVT engine models do not get the speed signal from the transmission. Those get it from the ABS/TRC/VSC computer as is shown below. One tire rotation generates 48 pulses and the pulses are processed by the ABS/TRC/VSC computer and sent to both the odometer and speedometer. The process is to remove the noise and to get the average and divide by 12. So the cluster unit receives 4 pulses when the tire fully rotates 1.
So just so I am clear..you are saying it could be one or more of the sensors on the wheels? or maybe the computer? or are you saying it is the actual speedometer?
I mean I could replace the ABS sensors myself and see what happens. But I would think if there was an issue with one of the ABS sensors I would see the ABS warning light while driving. I have no warning lights activated while driving. This leads me to believe the cluster itself is bad. Am I on the right track here?
Maybe I should remove the battery neg and reset computer? See what happens and go from there...
Sorry to say that you don't understand the problem correctly. You wrote,"the odometer works fine". It simply means that the output signal from the computer is OK. Only the speedometer is not working right. It can't be easily fixed by a Sunday mechanic. I think I can since I do have equipments and some skills to analyse the circuit.
Of course I don't understand the problem exactly; that is why I joined this forum so I could hopefully learn a thing or two and seek knowledge from those willing to share. I appreciate you attempting to help me but if you do not have the patience then maybe someone else will chime in...or I'll just have to figure this out myself.
I mentioned the odometer works correctly because in other threads about speedometers not working correctly; people would ask, "Does the odometer work or not?" and if "not" then tell the person to change the speed sensor on the tranny. I was just trying to provide more info. As for being a Sunday mechanic (if that is what you are calling me) I would argue that I'm actually quite mechanically inclined and very knowledgeable on pre '80's vehicles. I've worked on many old cars, trucks and motorcycles in my Dad's restoration shop before he sold it and retired. That said once cars started having computers installed in them I was lost. I just bought this car and will have to order a shop manual and study it. I was just trying to get a little help.
He is saying the odometer works so the problem is in the cluster speedometer part based on YOUR model year of the LS400,which changes over the years.You will either need to send cluster out for repair or replace it from junk yard and hope for the best,thats how im reading it.
Also Yamae is Japanese and THE expert on all things electrical,he is an engineer.So his translation not being a native speaker might sound harsh,far from it.He is a really good guy.You owe him an apology BTW,your reply was rude to someone trying to help you.For FREE.
As for your skills,if you arent an electrical whiz,most of what he tells us is well beyond what a shade tree mechanic can do.He is just telling you what is technically wrong per your info,how it works as designed,if you arent rocking an oscilloscope and have great soldering skills,circuit board repair skills,etc,its have someone else fix it time who can.
Some electrical we mortals can do,replace certain sensors for example,but the rest,waaaaay beyond most of us.
How does he owe him an apology??? All the rude and unhelpful comments posted across this forum. Ppl would always be apologizing. At least he searched before he posted his question. Yamae can defend himself.
All the rude and unhelpful comments posted across this forum.
Like that???Yeah,that was sure helpful and polite.Yes Yamae is a class act and an asset to this board.None finer.Has manners.Proud to know such a helpful,generous and overall fine person.And I'll say so.
First I'd like to say that I did a search and found plenty of speedometer problem threads but I could not find one with a resolution to my issue.
I just bought a LS400 ('99) at a dealer with 141k and I paid under 3k for it. It is in fine shape and runs beautifully. I needed a car to commute to work with (100 mile round trip per day M-F) and knowing how dependable these cars are I decided to buy this one.
The only major issue I have found so far is the speedo does not read correctly. The tach works fine, the odometer works fine and the car shifts beautifully. When I first start to drive the needle doesn't move (it is not stuck from what I can tell) and only once I get up to 20 mph or so it starts to rise. At 40 mph on gauge I am actually driving at 60 mph according to my GPS.
My first thought was the input / output speed sensors on the trans (I have replaced these before on my Hyundai XG350L so i am aware of when to replace these) but I am not seeing any telltail signs that the sensors should be replaced.
If I somehow missed a thread here on this exact issue then please link it if you don't mind. Otherwise; any ideas?
I would say contact these guys for a quick fix but it involves your car being down for a couple of days since you have to remove the cluster and ship it to them.
http://www.taninautoelectronix.com/category-s/1853.htm
He is saying the odometer works so the problem is in the cluster speedometer part based on YOUR model year of the LS400,which changes over the years.You will either need to send cluster out for repair or replace it from junk yard and hope for the best,thats how im reading it.
Also Yamae is Japanese and THE expert on all things electrical,he is an engineer.So his translation not being a native speaker might sound harsh,far from it.He is a really good guy.You owe him an apology BTW,your reply was rude to someone trying to help you.For FREE.
As for your skills,if you arent an electrical whiz,most of what he tells us is well beyond what a shade tree mechanic can do.He is just telling you what is technically wrong per your info,how it works as designed,if you arent rocking an oscilloscope and have great soldering skills,circuit board repair skills,etc,its have someone else fix it time who can.
Some electrical we mortals can do,replace certain sensors for example,but the rest,waaaaay beyond most of us.
I wasn't rude at all. The way he typed his responses I had a hard time understanding what he meant. That would be due to English being his second language I suppose. I appreciate his trying to help but I took his last response as him kinda talking down to me. I see now that it is more a language barrier issue than him actually talking down to me but I don't think i was rude. I'm not new to internet forums and I think even you will agree that typing words on the screen can sometimes be taken the wrong way.
Anyways...I'm not here to cause any trouble. Just a fellow LS400 owner seeking help and information. Your explanation of what he meant actually makes sense to me and I now understand so thanks.
I would say contact these guys for a quick fix but it involves your car being down for a couple of days since you have to remove the cluster and ship it to them.
http://www.taninautoelectronix.com/category-s/1853.htm
08-15-18, 03:20 PM
99 LS400 speedometer off by 20 mph. need input.
