speedometer died

[icsys]

As the title, my speedometer and has stopped working and it also doesn't clock up the km. The O/D light flashes once evry two seconds. Everything else on the cluster, tacho etc, works OK.

Also since the speedo stopped working (over a month now) the gearbox drops out of overdrive occasionally when travelling at speed (60mph ish). Dropping speed and clicking overdrive 'off' and then back on again gets overdrive to re-engage.
Is this a related fault or coincidence?

After searching the forums for ideas, speedo not working faults seem to be common, however I can't find a definitive solution.

This is what I have found out so far:

It could be the instrument cluster - everything seems to be OK with it. Nothing appears to be burnt out.

It could be loose wiring - everything seems to be connected OK, assuming I am looking in the right places.

It could be the gearbox controller - where is this and would it affect the speedo?

It could be the speed sensor - this is on the drivers side of the gearbox, part number 81318-120120 Is this the correct number?


The sensor is expensive, £150+ so would ideally like an indication that this is the fault before buying one.

Any help would be gratefully appreciated.
thanks.

[TonyN]

You can have the speed sensor out of a gearbox I have lying around for £20.

[stormforce]

what is the atf levels like as i don't think you have mentioned that.I would do an atf change and see if that cures it for the overdrive problem anyway

[stormforce]

You can have the speed sensor out of a gearbox I have lying around for £20.

I don't mean to question your knowledge Tony but on the toyodiy site the only speedo sensor they state is the one with the cog at the rear of the trans box.What are the other sensors then on the side of the gearbox then if going by toyodiy the one on the trands box is the speed sensor.Its just that i got a bit confused as i have seen other post saying about the other sensors being the speed sensors aswell

[BUSHWHACKER]

I don't mean to question your knowledge Tony but on the toyodiy site the only speedo sensor they state is the one with the cog at the rear of the trans box.What are the other sensors then on the side of the gearbox then if going by toyodiy the one on the trands box is the speed sensor.Its just that i got a bit confused as i have seen other post saying about the other sensors being the speed sensors aswell

There are two speed sensors on the transfercase adapter Rich, (the section between the T/case and transmission)
Basically, one is a road speed sensor, (with the white plastic cog) the other an engine speed sensor.

[stormforce]

There are two speed sensors on the transfercase adapter Rich, (the section between the T/case and transmission)
Basically, one is a road speed sensor, (with the white plastic cog) the other an engine speed sensor.

Cheers Vince.At least i know now whats what there.

[BUSHWHACKER]

Toyota speed sensors:
http://www.autoshop101.com/forms/h36.pdf

Just remembered I had this in my favorites list.
Page 1 shows vehicle speed sensor.
Page 6 shows speedo sensor.

Same sensors on the Surfs, except they are fitted to the T/case adapter and not the transmission.

[stormforce]

just saved that now.Thanks me ole mucker

[icsys]

Thanks for the info.

So the likely cause is the speed sensor.
Now I need to locate it correctly. As bushwhacker stated, there are several sensors on the gearbox/transmission case. Once I have correctly identified it I may take it out and just check it before taking TonyN's offer assuming we are talking about the same sensor.

In that PDF, on page 6, is it the MRE type VSS shown located at the transmission output shaft end?

As for the other problem, its been quite a while since I changed the AT oil.
Even then I just drained the sump and topped up. I believe doing that only changes about a third of the overall content so it could be well overdue a change.

Again thanks for your help.

[BUSHWHACKER]

The sensor for the speedo (MRE) is the one nearest the rear propshaft. Black plug, three wires.

[icsys]

I think I have located it, here are some pictures.

[BUSHWHACKER]

Yeah, thats the one.

You can bench test it if you have a multimeter.
Look at the plug end of the sensor and you'll see tiny numbers, 3 2 1.

Apply 12v to pin 1.
Earth pin 2. plus the negative probe of multimeter.
Positive probe of multimeter to pin 3.


Set meter to 20v DC, switch on power supply and turn the plastic cog on the sensor. The voltage reading should fluctuate between 0 and 9 volts, if it doesn't then the sensor is stuffed.

[icsys]

OK
Tested the sensor tonite.

Was getting 2.3v dc output on meter without turning.
No fluctuation when turning.

I guess the sensor is faulty.

[icsys]

You can have the speed sensor out of a gearbox I have lying around for £20.

Hi Tony,

If you still have that sensor can we arrange payment?
Unfortunately I dont have access to PM's any more.

[icsys]

OK

I changed the speed sensor for another one but no joy.
The flashing O/D light cleared but then started again. One flash every two seconds.

I double checked behind the clocks, no obvious faults there, no burning, all connections are clean, everything works except the speedo and odometer.

The speedo has never been converted, it is still KPH.

Not sure where to look next.
Can anyone offer any further suggestions??