Page 2 of 3
Re: Speedometer not working (all other gauges work)
Posted: Thu Jan 26, 2023 9:15 pm
by Tom
Yeah, until you definitively rule it out, the sensor seems the most likely culprit. I like the 3D tool. Definitely post it up in the STL section. One design idea would be to model a round post/rod on the end you can chuck-up in a drill. That would let anyone use it right off the printer with tools they have around the garage...

Re: Speedometer not working (all other gauges work)
Posted: Fri Jan 27, 2023 6:41 am
by Synapse120
Tom wrote: Thu Jan 26, 2023 9:15 pm
Yeah, until you definitively rule it out, the sensor seems the most likely culprit. I like the 3D tool. Definitely post it up in the STL section. One design idea would be to model a round post/rod on the end you can chuck-up in a drill. That would let anyone use it right off the printer with tools they have around the garage...
The diameter of the “tool” fit in my drill without any modification to the size. Once i get the square end at a decent size I’ll post it up in the STL section.
Re: Speedometer not working (all other gauges work)
Posted: Fri Jan 27, 2023 5:19 pm
by Synapse120
I performed all the tests and tapping ground from the sensor wire side worked in the car and i have 12V on the other two sensor wires. So it would appear my sensor is bad.
Apparently the the speedometer sensor is NLA from Porsche, and I’ve had bad luck with a used one
At some point all 944/951/968 on the road will have sensor problems and not be able to buy them.
Re: Speedometer not working (all other gauges work)
Posted: Fri Jan 27, 2023 5:45 pm
by Tom
Synapse120 wrote: Fri Jan 27, 2023 5:19 pm
I performed all the tests and tapping ground from the sensor wire side worked in the car and i have 12V on the other two sensor wires. So it would appear my sensor is bad.
Apparently the the speedometer sensor is NLA from Porsche, and I’ve had bad luck with a used one
At some point all 944/951/968 on the road will have sensor problems and not be able to buy them.
Well at least you got to the bottom of it. I'd be inclined to take one apart and see why it is not sending the signal. It has to be a pretty darn simple mechanical device -- it just sends 8 ground pulses for every tire rotation. There's also this:
https://944store.com/product/94460621000/
Re: Speedometer not working (all other gauges work)
Posted: Fri Jan 27, 2023 6:16 pm
by Synapse120
Tom wrote: Fri Jan 27, 2023 5:45 pm
Synapse120 wrote: Fri Jan 27, 2023 5:19 pm
I performed all the tests and tapping ground from the sensor wire side worked in the car and i have 12V on the other two sensor wires. So it would appear my sensor is bad.
Apparently the the speedometer sensor is NLA from Porsche, and I’ve had bad luck with a used one
At some point all 944/951/968 on the road will have sensor problems and not be able to buy them.
Well at least you got to the bottom of it. I'd be inclined to take one apart and see why it is not sending the signal. It has to be a pretty darn simple mechanical device -- it just sends 8 ground pulses for every tire rotation. There's also this:
https://944store.com/product/94460621000/
Since i have 2 of them that don’t work i was going to see how it comes apart and what i find inside. I’ll post pictures here and maybe if i can’t figure out someone else in the group may be able to help, if all else fails getting a refurbished one at least gives me options.
Re: Speedometer not working (all other gauges work)
Posted: Fri Jan 27, 2023 6:29 pm
by Synapse120
Here is what the inside of the impulse sender looks like
Re: Speedometer not working (all other gauges work)
Posted: Fri Jan 27, 2023 6:49 pm
by Synapse120
Here is the data sheet for the SS81CA on the sensor

- 656AAC6B-C5A6-4486-9DB0-513F84B67AB7.jpeg (1.52 MiB) Viewed 780 times
Re: Speedometer not working (all other gauges work)
Posted: Fri Jan 27, 2023 6:59 pm
by Tom
Appears to be discontinued, but not impossible to find new old stock...
https://www.radwell.com/en-US/Buy/HONEY ... CH/SS81CA/
Re: Speedometer not working (all other gauges work)
Posted: Fri Jan 27, 2023 7:37 pm
by whalenlg
I did find a new one in 2020 - but saw
dcauto has used stock for $55
Re: Speedometer not working (all other gauges work)
Posted: Fri Jan 27, 2023 7:48 pm
by whalenlg
I did find a new one in 2020 - but saw
dcauto has used stock for $55