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today on the way home my 04 CTT acted up again. PRND all light up and no gears selected but the car shifted and down OK. I used Durametric to pull a code and it indicated 

Input shaft speed inductive pickup-implausible signal, test conditions are not completed, fault is not currently active and causing a DTC light"

Any ideas of what is going on? I searched this forum, 6speed forums, and rennlist forum but no information regarding 721 code. I saw a threat mentioned PRND light up with 1314 code only. 

Any help will be greatly appreciated.


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Fault code P0721 - Output shaft speed inductive pickup [Output Speed Sensor Circuit Range/Performance]


Possible causes of fault

- 'Implausible signal', mechanical damage in sensor wheel or inductive pickup

- 'Implausible signal', inductive pickup faulty

- 'Implausible signal', Tiptronic control module faulty


(click to enlarge)



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Thanks Loren.  Let me give you a little back ground about my car so you can see more clearly what wrong with my car.  


Two days ago my 04 CTT stuck in 5th gear, no upshift or down shift. I took to an indy and he pulled a code 17105.  He said it is input shaft speed inductive pickup.  We ordered the part and had it replaced.  While waiting for the part to arrive, I parked my car in the garage.  One night I wanted to move it a little bit out of the garage and the car won't move.  I moved the shifter around, turned off and on. The car won't move at 2nd gear.  When it moved, it jerked strongly forward.  I let the tech know about this. He was able to replicate the issue. He replaced the input shaft speed inductive pickup and "reboot by remove all the cable" he said.  the car was driving fine last night but not as responsive as it was before.


This morning, when I stopped at a light, it shifted to 5th gear on its own. I had to shift around to get to 2nd gear.  I found an instruction how to reset computer gear in this forum and did it.  The car was more responsive.  Got to my work, parked the car, finished work day and drove home.  The car shifted to 5th gear on its own again at a light. I shifted around the shifter and got it to move but PRND all light up but no gear selector light up.  I drove home and felt the car did shift ups and downs smoothly.  I used Durametric to pull the code and it showed the message above.  


Now, you mention P0721 is output shaft speed inductive pickup.  why it said input shaft speed inductive in the message?  

in the table step 3 said replacing the control modules, will the tech know what it is if I print out this page and gives to him?


BTW, he did mention if the car acting up again, I may need to have the transmission reprogram by the dealer.  What do you think?

I read on rennlist and 6speedonline that some people are leaning toward using PIWIS for more accuracy than using Durametric.  What is your experience?


I  know I have asked a lot.  I really appreciate your experiences and professional opinions.  I am not a mechanic.  I am just a guy with an attitude of wanting to learn/to know, and get things done by myself if possible.  So pardon me if I don't communicate clearly about cars and its issues.  thanks again



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