Error 42 guaranteed fix?

Hi i`m having an error code 42. The speed sensor thingy. My search resulted in me rewiring some wires behind the speedometer but that didn`t help. Lately the speedometer drops to 0 km/h at random, tapping the dashboard is a good temporary solution but i find myself tapping the dash to much these days.

Symptoms:

Speedo drops to 0 km/h at random

Slip cont off starts flashing random

O/D off starts flashing after 3mins or so

Cruise Control doesn`t work

What to do to make this all stop? I heard the speed sensor is usually not the problem but the odometer electronics? Should i replace the odometer and see where that takes me?

The speed sensor in the gearbox does go quite a lot, its only a plastic cog. Id look at that as a matter of course.

Is that speed sensor No 1? thats what code 42 is about right? i have no knowledge other than gained from here hahah

If your speedo sometimes drops to zero, the odometer is not the problem. It'll either be the wiring behind the speedo (what exactly did you change?) or the speed sensor itself.

i read something about the odo working as an buffer or something, and that i should cut off 1 wire and attach the input directly to the output. Its on here somewhere

Yes, it does act as a buffer. That might even have been one of my posts. However, the odometer is downstream of the speedometer. Tinkering with the odometer will have no effect on the speedometer, and if the speedometer has an error (e.g. needle drops to zero when it shouldn't) then this should be fixed first.

And that problem could be related to the speed sensor connected on the gearbox? But how can tapping the dash solve a faulty speed sensor?

Well, if by tapping the speedo fixes the problem, I'd look and putting a replacement speedo unit in. If the speedo drops to 0 chances are theres a promlem with the speedo's electronic gubbins and this may affect everyting else as it all connected together!

Like heckler said. If tapping the speedo temporarily fixes the issue then you've probably got a marginal electrical connection either going into the speedo cluster or within the cluster itself. Leave the odo alone, that won't help you fix this. All your symptoms (slip cont, O/D off etc) are a result of the speedometer not picking up the speed correctly. Fix the speedo and everything should work again.

i`ll re-wire it to stock to see if that might solve anything. And try to get a hold of someone with a spare speedo wich might be hard in this Supra-rare country . The odd thing is tapping the speedo wont help anything, tapping the odo does :S

So, tapping the odo makes the speedo needle behave properly (albeit temporarily)? How odd. The speedo output feeds the odo input, not the other way around, hence the odo function is dependent on the speedo. The speedo isn't dependent on the odo.

Of course, if the loom's been hacked around then anything's possible. You could try another speedo cluster if you can get hold of one, failing that return the wiring to stock like you said.

Yeah odd right..i'll start rewiring to stock and see where that takes me