[revdarkwing]

Two days ago I got in my car after driving 30 miles normally and spending 30 minutes before driving again. When I started driving the car shifted much harder than normal (thunk) and was in limp mode. I drove slowly for about 5 miles then parked for about half an hour. When I restarted the car it was back to normal and has been ever since. I pulled the code and got the PO715 code only. Reading here and elsewhere I've learned it could be the plate or the sensor and on another model MBZ, I also read where it is possibly the 13 pin connector which is more easily replaced.
PS: The car has 120,000 (actual) on the odo.
My question is this. Where is this sensor and plate located? Does my mechanic have to drop the pan and drain the transmission to get at it or can is it outside the transmissions where it can be fixed without going into the tranny?
Since it only has happened that one time, I know it's something I need to do sooner or later and the cost will determine how long I try to stretch it before getting this done. There are other maintenance items I want/need to do soon and want to prioritize this one. Thanks in advance.

 

[barnesandrewj]

Two days ago I got in my car after driving 30 miles normally and spending 30 minutes before driving again. When I started driving the car shifted much harder than normal (thunk) and was in limp mode. I drove slowly for about 5 miles then parked for about half an hour. When I restarted the car it was back to normal and has been ever since. I pulled the code and got the PO715 code only. Reading here and elsewhere I've learned it could be the plate or the sensor and on another model MBZ, I also read where it is possibly the 13 pin connector which is more easily replaced.
PS: The car has 120,000 (actual) on the odo.
My question is this. Where is this sensor and plate located? Does my mechanic have to drop the pan and drain the transmission to get at it or can is it outside the transmissions where it can be fixed without going into the tranny?
Since it only has happened that one time, I know it's something I need to do sooner or later and the cost will determine how long I try to stretch it before getting this done. There are other maintenance items I want/need to do soon and want to prioritize this one. Thanks in advance.

 

[revdarkwing]

Thanks so very much... that was one of the things I was looking for and unable to find.
Can you enlighten me on what is involved in replacing the sensor if it comes to that? I didn't see anything in this video that even looked like one.

 

[cowboyt]

The speed sensor is on the conductor plate. That means you get to replace the conductor plate. Fortunately, those are readily available.

What you have to do is drop the transmission oil pan and remove the valve body. The valve body uses 10 bolts, so this is not difficult. The conductor plate is the large black thing that sits on the valve body. While you're in there, it's also a good idea to check the electrical resistance (any multimeter will work great) of your solenoids. Most should be nominally 4 ohms, and one pair will be 2 ohms.

After you replace the conductor plate, just put the valve body right back where you took it out of, put the tranny pan back on, fill 'er back up to spec, and enjoy driving once again.

 

[barnesandrewj]

The speed sensor is on the conductor plate. That means you get to replace the conductor plate. Fortunately, those are readily available.

What you have to do is drop the transmission oil pan and remove the valve body. The valve body uses 10 bolts, so this is not difficult. The conductor plate is the large black thing that sits on the valve body. While you're in there, it's also a good idea to check the electrical resistance (any multimeter will work great) of your solenoids. Most should be nominally 4 ohms, and one pair will be 2 ohms.

After you replace the conductor plate, just put the valve body right back where you took it out of, put the tranny pan back on, fill 'er back up to spec, and enjoy driving once again.

Thank you! Appreciate you sir! Mine was coming up for 60,000km oil change, so only research the video! Great to know.