Speedometer OFF/ON LS400

[Gebo]

My '98 Lexus LS400 has something going on with the speedometer. Tachometer and odometer work just fine. Every now and then when I first start off, the speedometer needle just stays at 0 and doesn't move. Everything else works
fine. Then after a few miles it will jump up and get to the right MPH. How do I diagnose?

 

[Tomioka]

If you have a scantool that can read live data check to see if you get an MPH readout when moving. If you have MPH readout when the needle is stuck at zero the ECU is receiving input from speed sensor and you might have a bad gauge stepper motor.

 

[Nick1994]

Smack the dash when it isn't working. The needle will probably jump up.

My brother's 96' ES300 did this. We pulled the isntrument cluster out and everything was tight, probably the instrument cluster itself.

 

[earlyre]

not even remotely the same vehicle, but, my 2000 Hyundai Sonata had a similar behavior from it's Tach.

I mentioned it when the car was in for some other warranty work (front passenger window regulator, IIRC), not sure if they replaced the whole cluster, or the tach itself, but from what i remember they said the tach itself was dead...

 

[JHZR2]

I noted such a behavior whe ABS sensors were getting flaky. Apparently one is used for speedo and one for cruise, so there's backup and things will work, but that jump was indicative of an issue.

Eventually a code was thrown.

That said, at 280k and 20 years of hot and cold, it could be the speedo itself.

 

[Gasbuggy]

Get on the Lexus specific forums. The LS400 has various cluster issues that show up around 20 years of age. Usually from failing capacitors, which you can replace yourself if you're good with a soldering iron.

I rebuilt my old 94 LS400 cluster and ECU myself. Fun fun fun.