Sensors! One got me, but was easy to fix.

[G31]

Let me add another sensor malfunction thread here. I was mowing and suddenly my MT3 47 dropped into limp mode. F02 S636.

I found a thread here and followed it to make this repair: MT3 Crank position sensor location??

It was the crank position sensor, and it was VERY easy to change. 14mm nuts on the starter, which needs to be removed to get behind it. Then a 10mm single bolt to hold the sensor on. I had to use a pick carefully to remove the black O-ring from the old sensor that stayed behind in the hole.

I did not remove power from the starter, since it only needed to be moved enough to get behind it. I laid it on a shop towel with wiring still hooked up. There is a plastic one-way retainer holding the plug part of the sensor onto the engine block, and it took a combination of a long flat screwdriver and pliers to remove. It was probably the hardest part due to annoyance.

3+ hours since the repair and the code has not reappeared.

 

[Fixastuff]

I don’t have that tractor but I appreciate how helpful this will be to someone else.
Thank you.

 

[Bobrown14]

Yup we were not the first to have this issue. Wonder if it was a defective part from the factory?

Where did you get your new sensor from??

 

[GS650GL]

You don't have to remove the starter, but it makes it a little easier. I use a 1/4" wobble drive extension with the 10mm socket to go over the starter to get the bolt out and then stick the bolt in the socket with grease so it won't fall out when putting it back in. The worst part is getting the wire connector unplugged with the stupid way they have it fastened to the engine. Bad crank sensors are pretty common, there is a service bulletin about how the manufacturer that makes them did some improvements to address the issue, but I wonder how many original version sensors are still in the parts system. My dealer stocks about 10 of them and they get them covered under the 5 year emissions warranty.