Speedometer Diagnosis
 

My speedometer quit today. I’ve been reading the forums and trying to diagnose what caused it to fail as to not waste a lot of time and money on fixing it. The basic symptoms were that the speedometer and odometer and trip meter all stopped working and the O/D light was blinking. Stopped the car after a few miles, shut it off and sat for 10 minutes. After restarting both were working, no blinking O/D light but the speedo was inaccurate. Not a little inaccurate but a lot like reading 22 mph when I was easily going 60 then it quit again. O/D light did not start back up again. Car seemed to shift fine and run fine throughout all of this
Looks to me like there are a number of suspects:
Speedometer Sensor
wiring from the sensor to the speedometer
the speedometer cluster
ECB
My thoughts on this are it probably isn’t the speedometer sensor at the transmission because it still shifts fine and that probably eliminates most of the wiring as well. I’m also eliminating the speedometer cluster since the problems there seem to be mechanical (ie lube leaking out causing the needle to stick) and the digital odometer quits at the same time.
So with all that I’m thinking it’s the ECB and probably the leaky capacitor issue talked about here. That being said am I missing something? Any thoughts from you guys that have lots more experience?
Thanks in advance.
1991 LS400

Leaking ecu caps will have nothing to do with the movement of the mph gauge. It's either the sensor like you said or speedometer. We fix those weekly. it's very common for an old cluster like that.

Also there is no "lube" in the needles. Needles reading much less or needles that don't move at all are both symptoms of gauge cluster problems.

It was either a coincidence or there is still something off with the transmission sensor.

If the odometer logs one mile at 60mph in exactly 1 minute then the problem is the speedometer. If the odometer is off then trans sensor.

Mine is the same way. I'll be going 70mph and the tach will be reading 1100 rpms. Seems the clusters are a common thing with these cars. Just have to save up to have it repaired.

Tack works - Speedometer Work Sometimes?
 

If it is just your speedometer that has stopped, (sometimes it will work again) and your tach is working fine, what is likely the problem?

Thanks,
Dave in SC

The gauge cluster is nearly always the problem for 90-92 with the exception of inaccurate fuel level readings.

I've been driving it for a bit and today the whole cluster went dead. :sad: Temp gauge, tach speedo, gas gauge and cluster lights. Nothing. The weird thing is the alarm for when you leave your lights on also quit as well as the auto seat adjustment (seat 1 and 2). I did check fuses they all look good.
I'm guessing I'll need to read up on pulling the cluster out and get it sent off and then take it from there.

I should have mentioned that mine was a 97.

Then it is always the cluster.

what about if its a 00 2nd gen?

Same concept. The cluster is likely the issue.

Smack the dash on top of the speedometer. See if it comes to life. I lived down at the beach for awhile and mine starting acting up. At the suggestion of some here, I did this. Had to do it every couple of weeks. Since I have quit living at the beach, it's given me no more problems.