My 96 5 spd. manual trans. Miata gets check engine light on.
The scanner reads the code PO500 (Speed Sensor A). I called
a dealer to purchase VSS, but was told that manual
trans. does not come with a speed sensor. Does anyone know
what parts need to be replaced?
The next question is where does the speedo cable go--do you have cruise
Likely locations for a speed sensor are at/in the cruise control, and at the
back of the speedo.
Do you have a mechanical or electric speedo meter? I thought that a 96 has
the electric speedo.
If so, It gets a speed signal from whatever the speedo cable from the tranny
Since a 96US model would be involved with OBD, possibly even OBD 1, the
codes may not match the later OBD2 codes.
It goes into the back of the speedo even with CC.
I think all 96 are OBD II, but I cannot swear to it.
>> There is a speed cable between trany and instrument panel, but not the >gear/wire. >>
>> > I believe your 96 has a speed sensor located on the manual tranny. Try
>> > Trussville Mazda (internet)
>> > looks just like an oversized speedo gear with a plug for wires instead >of a
>> > speedo cable.
>> >> My 96 5 spd. manual trans. Miata gets check engine light on.
>> >> The scanner reads the code PO500 (Speed Sensor A). I called
>> >> a dealer to purchase VSS, but was told that manual
>> >> trans. does not come with a speed sensor. Does anyone know
>> >> what parts need to be replaced?
>> >> Fory Horio
>> >> email@example.com
If it is an OBDII, it has an electric speed sensor at the tranny. If it's
something else, or a non US model, who knows?
I am under the impression that later NA's have an electric speedo and speed
Early NAs had the cable and were not OBDI or II (US models, anyway)
Perhaps this is a 96 with an earlier mechanical speedometer?. If so, I would
expect to see the speed sensor code from the ECU.
The reason I referred to the cruise control was that some cruise controls
have a digital speed sensor built in.
Really old ones had a stub speedo cable going to the speedo.
The 1996 miata that I took apart was OBD-II and it had the same type of
speedometer as the 1990 model, both driven by a cable from the
transmission and plugging directly into the speedometer.
I would need to check, but I think that the cable is the same part
number for any 1990-1997 miata.
Correct, I have never worked on a'97, so I can't say for sure there, but
I am almost positive that the M1's all have mechanical speedometers
unless they have been modified.
My mechanical one was the one that came with the car.
You can completely disable the cruise control on any M1 and the
speedometer will still work.
If a vehicle uses the cruise control to determine speed, doesn't that
make cruise control mandatory on the vehicle?
The OBDII ECU must get a speed pulse train from somewhere.
I've not seen a late model NA OBDII with a speedocable. (You always learn
So the most likely location for the speed sensor is actually in the
instrument console at the rear of the speedo.
Assuming that's where the speedo cable goes, and does not stop in between.
It does not. Maybe a pulse counter has been added to the speedo?
>> > I hate to agree with Pat, but Bozo is^H^Hwas an OBD II Miata and has
>> > the mechanical speedo cable.
>> > Darn, that hurt.
>> > Leon
>> Believe me Leon, the pain was mutual, as I was agreeing with your post >> as well. :-)
>> Come on, can't we be friends again? You wouldn't really club with with a
>> blunt object, would ya?
Ouch, there we go again with that agreement thing.
The cable looks the same for the 1990 and the 1996 model, straight from
tranny to the speedo. If the ECU needs a pulse counter for OBD-II, then
it must be taking it from the instrument panel.
Possibly, it is not a problem that I have heard of before, and
electronics are not my area.
Do you have a factory service manual? I find the factory ones cumbersome
to read and find what I need, but that information will be in there.
Since the back of the instrument panel can detect whether the ABS light
bulb is working or not, I am guessing that there are other areas, such
as the speed sensor, that can be tested there by a knowledgeable person
with the proper equipment.
If you do try the "swap the parts and see" method, I would suggest
trying to find a used instrument panel first, they are not hard to swap
on a 1996 model. The one from my wrecked '96 went for $65.00 about a
Finally, is your speedometer working properly?
While I have never heard of a faulty instrument panel causing these
codes, I have seen a number of posts about speedometer cables not
working properly, and both of the ones that I pulled sold quickly, so
that might be a potential source of the problem if it is slipping at the
speedometer because of a missing gear at the transmission side.
Yes, it was easy to take it out.
It's kinda odd that the odd meter works fine, but
speedometer is about 10% off. When I drive 60MPH,
it shows about 66-66 MPH.
Does the gear slipping show as a faulty "Speed Sensor"?
Not odd at all, they are two completely different instruments although
driven by the same cable. The odometer is a mechanical counter the
counts revolutions of the cable, the speedometer is an analog meter
driven by a rotating magnetic field opposed by a spring. As the spring
ages the speedometer can get more optimistic or the initial calibration
can be a bit off.
Changing tire size will, of course, throw both off.