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Discussion Starter #1
I have 94,000 miles on my 2014 q50s got it with 55,000 miles on it and my check engine light come on bring it to the dealership say it's my speed sensor p0720 anyone had this issue and what did you do to solve it
 

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Have you changed the speed sensor?
 

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No not as of yet wonder if any one came across this problem
P0720 - Output Speed Sensor

• The vehicle speed detected by the output speed sensor is 5 km/h (3 MPH)
or less when the vehicle speed transmitted from the combination meter to
TCM is 20 km/h (12 MPH) or more. (Only when starts after the ignition
switch is turned ON.)
• The vehicle speed transmitted from the combination meter to TCM does not
decrease despite the 36 km/h (23 MPH) or more of deceleration in vehicle
speed detected by the output speed sensor. when the vehicle speed detected
by the output speed sensor is 36 km/h (23 MPH) or more and the vehicle
speed transmitted from the combination meter to TCM is 24 km/h (15 MPH)
or more.

Most likely you have a harness or connector issue where the sensor circuit is open or shorted or the output speed sensor is failing. My bet would be on the output speed sensor needing replacement. It is located on the rear of the transmission.
 

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Discussion Starter #5
So I have to take apart the transmission.. and would that damage the Internal components inside transmission
 

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I believe that some disassembly of the transmission is necessary but I don't have a service manual for that model year. If the Jatco hasn't changed in layout, looking at the 2016 service manual, then it appears the rear extension on the transmission assembly has to be removed to access the output speed sensor. It looks like the tranny oil pan has to be removed also to disconnect the output speed sensor connector from the TCM.

You're looking at a fairly involved repair to get at the output speed sensor. I know I wouldn't attempt it.
 

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No, it's a small magnetic sensor that is just attached through the outer transmission body. It probably has a small 10mm screw that keeps it intact.
I'm not so sure that's correct. I'll look at it again.
 

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#26 on the diagram (AWD)

I understand what the sensor looks like. Perhaps I'm interpreting the schematic and diagrams incorrectly. Yes, #26 is the output speed sensor and it senses the teeth on the parking gear (#28) and emits a pulse to the TCM which converts that into vehicle speed.

Here is a drawing of the output speed sensor installed:



You can see the teeth of the parking gear (#28) next to the sensor. You can also see the bolt holes that attach the rear extension of the transmission assembly to the transmission. It sure looks to me that the sensor resides inside of that. housing.

While this is in Spanish, here is a teardown of the Infiniti transmission. If you go to aboutd 6:45 into the video, you will see him remove the output speed sensor. Sure looks internal to me.


Am I wrong or right?
 

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I understand what the sensor looks like. Perhaps I'm interpreting the schematic and diagrams incorrectly. Yes, #26 is the output speed sensor and it senses the teeth on the parking gear (#28) and emits a pulse to the TCM which converts that into vehicle speed.

Here is a drawing of the output speed sensor installed:



You can see the teeth of the parking gear (#28) next to the sensor. You can also see the bolt holes that attach the rear extension of the transmission assembly to the transmission. It sure looks to me that the sensor resides inside of that. housing.

While this is in Spanish, here is a teardown of the Infiniti transmission. If you go to aboutd 6:45 into the video, you will see him remove the output speed sensor. Sure looks internal to me.


Am I wrong or right?
I think both you and Lucky are right about the output sensor needs to be replaced so it's just a matter of locating where that sensor really is. I checked the RE7R01B for cross-reference (which is very similar to RE7R01A) and they're both in the same spot. And you may be right about it being inside the housing.

Here's another youtube video (in english) and that sensor is mentioned at around 7:30:

 

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I think both you and Lucky are right about the output sensor needs to be replaced so it's just a matter of locating where that sensor really is. I checked the RE7R01B for cross-reference (which is very similar to RE7R01A) and they're both in the same spot. And you may be right about it being inside the housing.

Here's another youtube video (in english) and that sensor is mentioned at around 7:30:

At about 11:15 into that video, he removes the output speed sensor. It is definitely inside the housing. Not something I'd want to do myself.
 

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At about 11:15 into that video, he removes the output speed sensor. It is definitely inside the housing. Not something I'd want to do myself.
well, me either. Ha!

Here's one of the PDFs I looked at when I was researching for 2016+ transmission changes. Unfortunately, I was unsuccessful but at least I found a more detailed info around this transmission. Output speed sensor is on page 12.

 

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Discussion Starter #16
I like to thank everyone that's help me out I was going to go to ammco cuz the guy say no problem we can take care of it but they got so much bad reviews I change my mind...I went to the dealer they say can do it for 1700 .but the also say some internal components might be damaged and suggested a new transmission
 

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6 months ago I had a Speed sensor fail. I was cruising on the highway with Cruise Control on. All of a sudden Cruise Control disengaged. I turned it on again and the same thing happened 30 seconds later. Then the dash lit up with AWD errors. I took it straight to my dealer where they changed the Right rear wheel speed sensor under warrantee. I was in and out in about 35 minutes..... it was a $75 part.
 
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