Speedo cutting out?

[jayparsons]

Hello...New '01 100 owner and very happy with the purchase, short of one issue...the speedo and odometer started to "lock up" on cold mornings, but seem to recover once the engine warms. Toyota tech at our local, rural dealer says "probably speed sensor, but no way to tell without replacing it." Before I spend $300 on a part that doesn't fix my problem, anyone had experience with this? I know very little about electronics, so I'm flying a bit blind here. Help?

 

[100 TD]

I expect the speed sensor would be a magnetic pickup sensor(could be wrong) they basically either work or they don't, they are a coil of wire with a magnet in the middle and either work or are open circuit, unless they are spaced too far away from the gear or ring which activates them. I would check wiring connections,plugs and damage to cables.

 

[jayparsons]

Ok, I should have listened, but a new $300 speed sensor later and the issue still exists. Seems to "repair" itself once the engine comes up to normal running temperature. Does this sound like a loose connection that's magically making enough contact once the temp increases enough?

Should I expect to get any $ back from the dealer for the mis-diagnosis, or am I sunk?

 

[100 TD]

Ok, I should have listened, but a new $300 speed sensor later and the issue still exists. Seems to "repair" itself once the engine comes up to normal running temperature. Does this sound like a loose connection that's magically making enough contact once the temp increases enough?

Should I expect to get any $ back from the dealer for the mis-diagnosis, or am I sunk?

"YES" as the speed sensor output can be tested.

Ideally the fault needs to be diagnosed "when the fault is there" so leave at dealer overnight for them to test first thing.

From manual........The No.1 vehicle speed sensor outputs a 4-pulse signal for every revolution of the rotor shaft, which is rotated by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the ECM. The ECM determines the vehicle speed based on the frequency of these pulse signals.

It can be tested by jacking up a wheel and rotating it and measuring a 4 to 6 volt pulse.

 

[jayparsons]

Thanks for the response and suggestion...I'm going to do just that, leave it overnight. My Toyota guy was a little embarrassed when I called him so hopefully he'll refund me some dough.

Thanks again...will post back when I get the real issue identified and fixed.