2008 Mustang GT Transmission Swap Wiring Problem

Hello Guys, I'm new and I'm breaking the unspoken rule of asking for help before giving any but I'm hoping that with your help I will be providing help to someone in the future with getting this solved. Ok, So for 2 Months now i have been trolling every forum and bought a Haynes Manual but cant figure it out. I have a 2008 Mustang GT and I did the transmission swap from Auto to Manual (Yes i know you all hate it and i should never do it but its done so stick to the problem at hand) EVERYTHING went great but one thing. (Note: i reused the Auto PCM and Auto Wire Harness and got a new tune with my bama tuner) My Speedometer does not work and I'm in Limp Mode with Code P061C. Now your first guess of bad speed sensor, already tested and replaced, both passed. Did a continuity test from the sensor to PCM and it was good, went as far to jack up the car, put it in gear and check for A/C Volts at the PCM. I looked up wiring diagrams for it but the best i could find was what ever one uses and it says 05 to 07 and i checked all the pin outs and they are correct (but could they have changed it mid 08?). I thought maybe the ABS speed sensor my play a part in giving information for speed like so cars but research says no and i have no ABS lights or TCS Lights on. I Checked for Ground, PCM works fine becasue they is nothing else wrong wit the car it runs fine just wont rev over 4k RPMs. I'm at a Complete lose and I'm hoping I over looked something because its a 08 and i followed the forum by Anothy05GT for his 05. So your mission if you choose to accept it is to help figure this out so the next time it happens they can troll my post and get the info they need!

Usually that code has to do with crank or cam sensors. Check your crank sensor and the ring for any damage. If it's not a sensor it will probably be wiring or PCM.

Could also be the tune.


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Get another tune not from AM, or atleast have them recheck.

Could be the tune.

My first drive after I put in my new motor and TR6060 swap did not have a functioning speedometer and car went into limp mode. It did not throw that particular code but threw many other codes.
This was just a small mistake from a competent tuner in my case so I am betting that there is no way one of the 'bots at Bama would get this one right.

Also, with the problems that the 5R series transmissions have, only a few people would look down on you for wanting to put a transmission that is much more fun to drive in your car. Plus, this is a board for people to find help and learn about these cars. None of us here were born knowing everything about these cars, you do not need to feel obligated to provide help before asking for it.
Welcome!

I did a Cam Sensor Test on both and they are reading fine. If one was bad would the engine still run fine? and it wouldn't explain the speedo.
also i spent a month battling Bama. They sent me 3 tunes and have me go stock and reload it. i sent data logs also. They say its a mechanical issue, I think its a tune also but they have all but stopped helping. I actually called a local mustang Yoda but he inst free till next Thursdays to look at it.

Also thanks for the Reply's!

The cam sensors would not have anything to do with the speedometer not working.

There were a couple revisions to the wiring harness but I do not know what they are specifically. I believe the changes were in 2007 so maybe double check. That being said, if the speed output sensor plug from the auto harness plugs directly into the sensor on the new transmission, I highly doubt that they would have changed the pin location between a manual and automatic car.

Bottom line, find a new tuner. Seems like the common denominator in a lot of threads these days is Bama .

I Think its the Tune too, also I've looked everywhere for a transmission wiring diagram that says 2008 but the only thing i can find says 2005 to 07 and that even in the haynes manual! I feel like i discovered a ford mustang cover up! lol If any one can find or has the 08 or newer please email me. Also I forgot and i think this is because of limp mode but when I'm driving and I push in the clutch (coming to a light or stop at speed) the RPMs drop off hard some times even stalling the car, its really bad when I down shift in 3rd. i actually have to keep it in 3rd and softly pop the clutch to catch the RMPs. Limp Mode or possibly a clue?

Also this is the wiring I used. and everything pin outs out right

so i checked the cam and crank sensor and they are all good.

So Update..... I Got the car to work! Solution was to install an Manual PCM (I Used the Auto wire harness after do the steps needs to work as an manual) and i installed a simple jumper wire on the pins under the dash where the clutch wiring harness goes (couldn't find one) Note....YOU CAN reuse the auto PCM to manual on 05 and 06 ONLY! 07 to 10 need to use a Manual PCM with PATS turn off and a Jumper wire or clutch wiring harness. Also only 07 and 08 can be swapped around the same for 09 and 10. but you cant do 09 and 08 or anything. i hope this helps someone, if you need any info please email me.

cmcdowell said:

So Update..... I Got the car to work! Solution was to install an Manual PCM (I Used the Auto wire harness after do the steps needs to work as an manual) and i installed a simple jumper wire on the pins under the dash where the clutch wiring harness goes (couldn't find one) Note....YOU CAN reuse the auto PCM to manual on 05 and 06 ONLY! 07 to 10 need to use a Manual PCM with PATS turn off and a Jumper wire or clutch wiring harness. Also only 07 and 08 can be swapped around the same for 09 and 10. but you cant do 09 and 08 or anything. i hope this helps someone, if you need any info please email me.

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Glad you got it sorted out and thanks for sharing your solution !