Hi, I have 3 Lexus ls400's and all 3 of them the tachometer does the same thing. I attached a pic of how it always points below 0. Is there a fix for this?

 

I figured it out. I ordered in some capacitors and replaced them on the ECU and all problems have dissapeared.

 

Impressive.

 

Good to hear. Can you be specific about what years you did this on, and what+where capacitors did the trick?

BTW, my experience from looking into a similar problem on my '91 is that they made a lot of changes back in the early days, from year to year on the tach and speedo. So some years fail due to one problem, and other years fail due to something completely different. (e.g., a mechanical/lubrication issue with the needle vs. capacitors on the circuit board = pretty different)

And also, it seems that a lot of these fixes are closely held secrets, known to a few who try to make a business out of it vs. sharing the knowledge. No moral judgment from me on that one, but it's frustrating when you go looking for details and they are not revealed.

 

I encountered exactly this on my 1991 as well. my tachometer needle was loose on the motor shaft, so I repositioned it and very lightly glued it on (even the smallest amount of glue can jam the needle). No problems since that fix, and the tachometer reading matches the computer's information.

OP, after your capacitor replacement, does your tachometer needle start and stop at exactly 0, and are the RPMs accurate? Typically, when the needle comes off the shaft, it rests below 0 like yours does in the photo. If the needle is moving now, but the RPMs aren't accurate or the needle sits below 0 (when car is initially turned on or after it is turned off), then there it still needs to be reseated.

I've made posts on tachometer and speedometer needle adjustments in the past that can be looked up on this forum.