2006 Check Engine Light. Need Help

Chuck wrote:
> 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?

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.

> I am under the impression that later NA's have an electric speedo and speed
> sensor.

No.

> Early NAs had the cable and were not OBDI or II (US models, anyway)

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.

> Perhaps this is a 96 with an earlier mechanical speedometer?. If so, I would
> expect to see the speed sensor code from the ECU.

My mechanical one was the one that came with the car.

> 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.

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?

Pat

Leon van Dommelen wrote:

> 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?

Pat

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
something new.)
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.




"pws" > wrote in message
...
> Leon van Dommelen wrote:
>
> > 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?
>
> Pat

"Chuck" > wrote:

>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
>something new.)
>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?

Leon

>
>
>
>"pws" > wrote in message
.. .
>> Leon van Dommelen wrote:
>>
>> > 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?
>>
>> Pat
>
--
Leon van Dommelen Bess, the Miata Bozo, the Miata
http://www.dommelen.net/miata
The only thing better than a white Miata is two white Miatas

Leon van Dommelen wrote:

> It does not. Maybe a pulse counter has been added to the speedo?
>
> Leon

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.

Pat

I do see a cable goes straight from trans to instrument panel.
So, do I need to replace the instrument panel in order to
repair the "Speed Sensor A P0500" check engine light problem?


pws wrote:
> Leon van Dommelen wrote:
>
>> It does not. Maybe a pulse counter has been added to the speedo?
>>
>> Leon
>
> 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 instrument panel.
>
> Pat

PS My car does not equipped with a cruise control.


pws wrote:
> Leon van Dommelen wrote:
>
>> It does not. Maybe a pulse counter has been added to the speedo?
>>
>> Leon
>
> 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.
>
> Pat

Fory Horio wrote:
>
> I do see a cable goes straight from trans to instrument panel.
> So, do I need to replace the instrument panel in order to
> repair the "Speed Sensor A P0500" check engine light problem?

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
year ago.

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.

Good luck!

Pat

pws wrote:
> Fory Horio wrote:
>>
>> I do see a cable goes straight from trans to instrument panel.
>> So, do I need to replace the instrument panel in order to
>> repair the "Speed Sensor A P0500" check engine light problem?
>
> 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
> year ago.
>

Yes, it was easy to take it out.

> Finally, is your speedometer working properly?
>

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.

> 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.
>
> Good luck!
>
> Pat

Does the gear slipping show as a faulty "Speed Sensor"?

Fory Horio > wrote:

> It's kinda odd that the odd meter works fine, but
> speedometer is about 10% off.

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.