Speedometer inconsistency

I just picked up a 2005 TRD Sport 4x4 V6 6-speed with 110k miles on it. I'm pretty stoked on it so far but driving 6 hours home from where I bought it I noticed that the speedometer is all over the place. Compared to GPS it is anywhere between +/-12mph. Once sitting in traffic at a dead stop it read 10mph. Sometimes it right on. I am new to Toyotas but very experienced with German cars and muscle cars. There are no ABS lights and the odometer seems to work correctly. I need to check the speed sensor output on a OBD2 scanner. When changing the transmission/transfer case oil I looked at the sensor on the tailshaft of the transfer case and it didn't look damaged at all, wiring seemed ok as well. Most of the posts Ive read on here have to do with speedometer calibration for bigger tires, the speedometer not working at all and or lots of lights on the dash. Any ideas? Im guessing a bad gauge cluster if the speed sensor output is ok?

 

Here's a pic of the truck the other day at a red light. Speedometer reads 7mph stopped at a redlight. That morning the speedometer was deadnuts accurate to the GPS, on the way home it was all over the place.

 

Soon it will stop working, had same situation, end up changing it.

 

Did you put in a new or used one? Did you have to calibrate it to get the proper odometer reading? I'm used to BMWs that store the mileage in three different modules and used odometers give you a tamper dot saying mileage is incorrect.

 

I haven't calibrate it nor check against gps, but at least it stay at cero when park, and move consistently when in road.

 

Does the new cluster odometer show the same mileage that your old one did or does it start back at zero?

 

I need to know this as well, I heard its stored in the speedometer, but I'm not sure. I change the lights in mine a burned it a little bit..

 

You mean total miles? it has the miles of previous truck, the one it was took out

 

Exactly, it stored in the speedometer

 

My old Grand Am stored the mileage in the odometer. I believe it also stored it in the ECU, but I had swapped that, odometer didn't change.

 

This is getting worse now. 30mph at a stop! I was looking online and it says my gauge cluster is a discontinued product and is longer available? PN 83800-04890. I called a few
Speedometer places in LA and none of them can fix it.

 

Put some gas in your truck. There are some sites online that will repair clusters. Most cluster repair places specialize in Ford and gm clusters. Very rare to see one go out on a Toyota.

 

@Bebop Could it be the TPS? Had one go out on my old F150, caused the transmission to grenade (because I drove it, trying to get it home lol).

 

Doubt it. Tps controls transmission shift times. Like when you put your foot on the gas it's suppose to kick down into a lower gear. I had one go out in my first gen and it was stuck in overdrive. Had to manually change the gears when driving.

 

Mine is a 6spd so I always have to manually change the gears. I don’t foresee it being the speed sensor because The truck doesn’t run weird and sometimes the speedo is dead on with the 265/70/17s on my truck.

 

Didn’t work at all on my way home from Work now. Odometer works though, and I got gas!

 

Possible faulty speed sensor?

 

San Diego area is full of auto dismantlers. Judging by online prices $125-150 would be reasonable and they usually guarantee it will work or bring it back. Youtube instructions for disassembly, it looks pretty easy.

 

Disassembly of the speedo itself in the cluster or removal of the cluster? Ive had the cluster out to route the Bluetooth mic. Its not that hard. The price is reasonable, worried about the mileage on the odometer being incorrect.

 

My first suspect would be to check out the transmission speed sensor that sends the signal to the instrumental cluster, it could be sending invalid signals resulting in your troubles. It's rare that clusters ever go bad, especially with my experience from Toyotas. You can change out the Guage and have the mileage corrected, but it'll have to be done at a dealer who has the capability to do so.

The speed sensor is a much cheaper fix and worth looking into.