Mustang Cobra--How to covert and ABS Sensor into a Speedometer Sensor

[BurnTire]

This is a method to make an ABS sensor to works as a speedometer sensor. This is helpful for those converting to an auto transmission. The price to make a TH-400 work in a conventional manner was several hundred dollars. That drove me to look for a more affordable solution.

Thanks to 03steve & street lethal for providing info to make this tutorial possible.

This is how I tied into the Right Front ABS sensor.

Warning
This is for a car that does not have functional ABS.


YE/RD is (+) Positive
YE/BK is (-) is Negative

2785


Go to the right fender remove the tire and liner then locate the ABS connection.
I cut the ABS connector out and taped off the Yellow wires going to the PCM.

This connector replaces the speedo connector on the tranny harness. 2787

After you cut the connector out you will have still have a Black and Brown wires going to the ABS Tone Ring. (You need to extend these ABS wires out to the tranny harness)

The Black is +
The Brown is -

Purchased some new Red and Black wire.


Connect the new Red wire to the (+) Black wire going to the ABS Tone Ring
Connect the new Black wire to the (-) Brown wire going to the ABS tone Ring



I routed the wire thru the antenna grommet then behind the glove box and radio then down under the shifter bezel to tranny tunnel.



Now take the ABS connector you cut out and attach it to the new wiring in the tunnel.
Attach the new red wire to the (+) black wire on the connector.
Attach the new black wire to the (-) brown wire on the connector.



Now it is time to tie into the speedo wiring.

Locate the (OSS) Output Shaft Sensor connector (Speedo) on the tranny harness. I cut the T-56 OSS connector off as the ABS connector above replaces it.

The OSS wiring is
DG/WH (+) positive
GY/RD (-) negative
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Connect the (OSS) DG/WH + to the (ABS) Connector YE/RD +
Connect the (OSS) GY/RD- to the (ABS) Connector YE/BK -

Now you are done with the wiring and have successfully created an removable connection.




Now the tune must be adjusted.
The PCM needs to know how many turns of the OSS are required to make one revolution of the tire.
The Front Tone Ring has 50 teeth.

So you need to set the following parameters in the tune

Number of holes for OSS sensor 10
Axle Ratio 5.00
Tire Revs Per Mile - (Set based on front tire data)

The PCM will now calculated one tire revolution based on 50 pulses which is how many teeth are on the tone ring.

GPS tested and accurate within 1MPH.

[no_slow_svt]

you cant just tap into the wires and still leave them connected to keep the abs functional?

[BurnTire]

you cant just tap into the wires and still leave them connected to keep the abs functional?

I have no data on that, but I think it could possible work.

You can also have a GM electric setup installed in the TH-400 as long as you have and evenly spaced teeth on the reluctor wheel. I believe the wheel has 40 teeth and some machine it down to 5 evenly spaced teeth.

[no_slow_svt]

^ that sounds like to much messing around for me.:)

[no_slow_svt]

can you turn the ABS light off in the tune if you want to, do ya know?

I tryed to keep everything hooked up and just splice into the harness, and my ABS light is on now. so im guessing it didnt work. but i have yet to drive it on the street.
ill keep ya posted if it does work though.
J

[BurnTire]

can you turn the ABS light off in the tune if you want to, do ya know?

I tryed to keep everything hooked up and just splice into the harness, and my ABS light is on now. so im guessing it didnt work. but i have yet to drive it on the street.
ill keep ya posted if it does work though.
J

No the light will stay on. There is no way to shut it off in the tune.

If the ABS light is on it is not working. Are you trying to make this work with the ABS?

[no_slow_svt]

you cant just tap into the wires and still leave them connected to keep the abs functional?


yeah i tryed to tap into one of the rear sensors like this.
i dont have the car on the ground yet, (wating on my driveshaftstill)
once get it on the ground ill be able to tell beter, then ill play with the wires to see whats going on.

[no_slow_svt]

burn, i switched the wires around and still nothing.

what is the reason for reusing the connector?just to make disconnecting it simple(if you need to)

basicly i took the two wires coming off the speed sensor on the trans and ran new wires right back to the black and brown wires coming off the abs sensor.

am i missing something?
its simple stuff i thought,I havent adjusted anything in the tune yet, but i wanted it to at least register something before i adjust the tune.

[BurnTire]

burn, i switched the wires around and still nothing.

what is the reason for reusing the connector?just to make disconnecting it simple(if you need to)

basicly i took the two wires coming off the speed sensor on the trans and ran new wires right back to the black and brown wires coming off the abs sensor.

am i missing something?
its simple stuff i thought,I havent adjusted anything in the tune yet, but i wanted it to at least register something before i adjust the tune.

I used the connector to make it removable if need be so it is not necessary. I assume the t45 uses an OSS like a T-56, but I am not sure.
Are you driving the car to verify it is not working?

[no_slow_svt]

I used the connector to make it removable if need be so it is not necessary. I assume the t45 uses an OSS like a T-56, but I am not sure.
Are you driving the car to verify it is not working?
yeah im driving it. ive switched the wires back to how they were in the first place. and still nothing, checked all the fuses too and those are good.

im stumped, and i hate these kinda problems. electrical sucks!! lol

[BurnTire]

Ok did you cut the wires from the ABS sensor or did you just tap into them? If you still have the wires going to the ABS module it may not work as that method is not what I used. Also make sure you are hooked into the speedo harness correctly.

[BurnTire]

Did you get that speedo figured out?

[no_slow_svt]

Did you get that speedo figured out?
heck no :(
you dont think it needs to be changed in the tune in order for it to pick it up do you?

i was thinking it should pick it up without changing anything, and then adjust it in the tune.

[BurnTire]

heck no :(
you dont think it needs to be changed in the tune in order for it to pick it up do you?

i was thinking it should pick it up without changing anything, and then adjust it in the tune. If the connection is working it should see a signal just not the correct speed. Can you hook the ABS back up to the sensor to verify the sensor is working or check it with a volt meter. It toggles ground. Are the wires on the speedo harness the same color as my 03/04? Do you have a wiring diagram for your car?

[no_slow_svt]

If the connection is working it should see a signal just not the correct speed. Can you hook the ABS back up to the sensor to verify the sensor is working or check it with a volt meter. It toggles ground. Are the wires on the speedo harness the same color as my 03/04? Do you have a wiring diagram for your car?
im going to hook it back up to the abs tomorrow. (maybe i messed it up when i orginally had both hooked to it,(speedo and abs))
if the sensor is messed ill try hooking it to the other side, and keep my fingers crossed.


pretty sure the wires were the same color as the 03/04,
thats one of the first things i did after the 5 speed broke, so i dont remember for sure

[no_slow_svt]

i pulled my trans back down to get the converter tweaked, so im looking into getting my speedo going again.(i gave up on it last year)

I now have the Gm style parts being shipped to me also,

burn, do you remember is your gy/rd wire was hooked to others in the harness?

the wires i had hooked up were the green/white for positive and the gray/red for negitive.

[no_slow_svt]

yeah, it looks like the gray/red is the ground for the rear 02's and the speed sensor,

my Haynes book says gry\blk and pnk\org for the vehical speed sensor.

thinking back, i only had to redo 4 wires for the whole swap, 2 being the reverse light wires(which the reverse lights work on my car) and the 2 wires for the speed sensor on the tail shaft.
and those wires were gray/red, and green/white

[BurnTire]

i pulled my trans back down to get the converter tweaked, so im looking into getting my speedo going again.(i gave up on it last year)

I now have the Gm style parts being shipped to me also,

burn, do you remember is your gy/rd wire was hooked to others in the harness?

the wires i had hooked up were the green/white for positive and the gray/red for negitive.

Sounds like you have it right.

Connect the (OSS) DG/WH + to the (ABS) Connector YE/RD +
Connect the (OSS) GY/RD- to the (ABS) Connector YE/BK -

You hook the two wires on the harness that go to the speedo sensor on the tranny to the two wires on the ABS sensor. Mine works fine, but I am not sure of the ABS method works with a functional ABS system.

[no_slow_svt]

yeah I can care less about the abs....I really just want the speedo to work again