Speed sensor problem-3.8 L

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

tagroover - 26 Feb 2006 22:27 GMT

I have a low-miles 94 Sable 3.8 L. I only get a road speed after warm up.
When cold, electronic speedometer and transmission don't get speed reading,
causing transmission to go bonkers, problems disappear after 15 min. Already
spent $200 replacing sensor and connector. Tried swapping ECM. Measured
sensor resistance, 197 ohms hot, 213 cold. Is it possible sensor isn't
spinning? I can't reach in there and feel it to find out. Any ideas?

Reply to this Message

Backyard Mechanic - 28 Feb 2006 03:02 GMT

> I have a low-miles 94 Sable 3.8 L. I only get a road speed after warm
> up. When cold, electronic speedometer and transmission don't get speed
[quoted text clipped - 3 lines]
> it possible sensor isn't spinning? I can't reach in there and feel it
> to find out. Any ideas?

I thought someone might have a better idea than myself on this one... but
since I have nothing definitive, why not try leaving a drop-lite with a 40
to 60 watt bulb in the cabin, overnight, so that the heat from it rises to
under the dash... be careful you isolate it so nothing melts.

Then if the symptom doesnt show, or resolves quicker, that might be a clue

Signature

Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!

Reply to this Message

Bob - 28 Feb 2006 04:08 GMT

>> I have a low-miles 94 Sable 3.8 L. I only get a road speed after warm
>> up. When cold, electronic speedometer and transmission don't get speed
>> reading, causing transmission to go bonkers, problems disappear after
>> 15 min. Already spent $200 replacing sensor and connector. Tried
>> swapping ECM. Measured sensor resistance, 197 ohms hot, 213 cold. Is
>> it possible sensor isn't spinning?

Yes it is possible, the VSS drive gear is (believe it or not) made out of
plastic. I've seen several of them worn to the point where the VSS would
stop turning. The worst part is that it requires trans removal and complete
disassembly to replace that $2 gear. That may not be your problem but... you
asked if it was possible. If that is what's going on with your trans a new
VSS gear might buy you some time. For what it's worth the cars I've seen
with this problem were all high mileage. Good luck
Bob

Reply to this Message