My transmission was shifting erratically. Symptoms: on take off it banged into gear sometimes, sometimes it would not shift and had no power on take off or when coming to a stop it banged into a lower gear. In addition to all of that, the O/D light was flashing on the shifter. When I FINALLY got home, I immediately hook the scanner up and got code (P0715 Input/Turbine Speed Sensor Circuit Malfunction) or Turbine Shaft Speed Sensor (TSSS). I figured this sensor tells the computer when to shift etc. The Haynes manual does not talk about this particular sensor.

This is a description I found on the TSSS from wikepedia:

This may also be known as an input speed sensor (ISS). This sensor sends a varying frequency signal to the TCU {transmission control unit} to determine the current rotational speed of the input shaft or torque converter. The TCU uses the input shaft speed to determine slippage across the torque converter and potentially to determine the rate of slippage across the bands and clutches. This information is vital to regulate the application of the torque converter lock-up clutch smoothly and effectively.

Here's a description from another site:

The Turbine Shaft Speed (TSS) sensors a magnetic pickup that sends the Powertrain Control Module (PCM) information on the rotation speed of the coast clutch cylinder assembly The Turbine Shaft Speed (TSS) sensor is mounted externally on the top of the transmission case. The Powertrain Control Module (PCM) uses Turbine Shaft Speed (TSS) sensor signals to help determine Electronic Pressure Control (EPC) pressure, shift scheduling the Torque Converter Clutch (TCC) operation.

I purchased the Turbine Shaft Speed Sensor (TSSS) from Ford for $34 (P/N F81Z-7m101-AA). It's kind of a pain to replace. You don't have to drop the transmission to do the job though but you will need to be pretty flexible. FYI: the TSSS and the output speed sensor (OSS) are identical. I purchased 2 to replaced both but I have yet to find the OSS. It seems to be on the very top of the transmission. So if anyone knows where it is located please let me know.

First, I had to locate the TSSS (the picture from the dealer was no help). I used a flash light, mirror and my hand; it's located on the drivers side about 1 o'clock if your head is pointed toward the front of the truck or 11 o'clock if your head is facing the rear. It is very, very tight in there (4x4) so I had to remove the front drive shaft and lower it out of the way (didn't have to remove completely but just enough to allow my hand up in there).

To remove the drive shaft, you will need a 12mm 12pt shallow socket, a crow bar or large screw driver to keep the shaft from spinning and a breaker bar (I used a 18" bar). Don't forget to mark one of the bolts so that you can reinstall it as it came out and don't spin the wheels or the front flange/yoke will rotate.

To remove the TSSS, you need a small ratchet (not a lot of space) and a 5/16" shallow socket (the screw that retains the TSSS is very short - about 3/8 -1/2" so not a lot of turning is required. Do not attempt to remove the connection from the TSSS while it's on the transmission, just wait until you remove it - much easier. Do the reverse to replace the TSSS. Reinstall the driveshaft and torque to 68-85 ft/lb. I torqued to 85 ft/lb.

I just recently completed the job and update.

 

Hey, Thanks for the post... im throwing the same code so im going to attempt this next weekend.

 

Methodical

I was throwing the same code. I replaced the sensor (45 min for a one bolt job was a let down). I went for a test drive and threw the same code again with the new sensor. Is there anything else that you stumbled across that might be the reason for this? It is a completely stock 06 with a relatively fresh tranny.

 

Erase your code, disconnect the battery for 15 minutes to reset it. Re attach, start and drive normally for 30 or so miles. See if condition is remedied or something else happens. If you get the code again, look at your wiring for damage around the area or up along the wire loom. It may be hot/melted, rubbed or just a damaged connector internally. It happens with much disappointments. Even check the fuse to make sure it is in contact properly.

 

I did reset the code and popped the same code after driving with the new sensor. I was hoping it wasn't a wiring issue because that usually ends up being more work than I like. I didn't think about checking a fuse. Do you know which fuse it might be. I don't have a book on the truck yet. Thanks for the input!

 

Check your transfer case output speed sensor, they are in with each other on the circuit. Also the plug on that side at the rear of the engine.

 

Alright, is there a way to check if the sensor is good without having to throw a new one in? I wasn't able to locate the output speed sensor. I about the same as the input, just further back. As for the plug... are you talking spark plug? I wouldn't think they would be connected like that. So far, I have replaced the input speed sensor, traced all the wiring involved (there are no loose wires or corroded connections), and checked and double checked every fuse I have.

 

I know its a little late in the game to be asking this question since I already have the part, but I am going to ask anyway. Since the input shaft speed sensor counts revolutions of the input shaft, are the sensors different from gas to diesel engines? The new sensor that I put in looks different than the one I took out, but I just chalked that up to being from a different manufacturer. Could this be my issue?

 

Won't hurt to double check that part. It's for sure a simple problem. You got a code, you replaced the part, didn't fix it. So you look to the wiring and connectors in the circuit. It's either the sender or the other one.

 

I have a Ford Explorer Sport track and I have the same problem
Is this sensor is located in the same position in the transmission of my 2001 Sport track I got already the new sensor to replace, I jack up the truck but I still have problem how to find it!
If you have more detail please let me know
Best Regards.
David

 

I'm having trouble locating the input turbine speed sensor on my 17 F250 STX 6.2L with a 6R100 transmission. is it on the inside? throwing a P0715 code. any help would be appreciated.

 

did you ever get this fixed having same issue with my 18

 

Karl, you will probably get a response if you post your question in the correct section. You are asking on a 2012 post about Expeditions. And yes your sensors are inside the 6R series transmissions.