Larry Bacon

@enigma-2 My 2020 ST has had the C0090:71 since August last year. I clear it and it comes back. I just drive with advance track turned off and it doesn't set the code or drive in sport mode. I do know that it isn't getting power to rear wheels since we have snow currently and I can tell it isn't awd even when it shows on dash with advance track off. Do you happen to have the diagnostic break down for the code that when it warms up I could possible trace out the issue? I was in a drag n drive event and was reflashing my tune when it threw the C0090:71 code, and the pre-collision and hill start not available. Thank you,

Okay I've read thru a lot of this post and here is my issue that I am having. First weekend of August my AWD service wrench came on. I scanned later and found the C0090:71-24 code. I had set a appointment to have trans, rdu, and PTU serviced before hand. I've tested and looked at different things and clear code and it will come back in roughly 6.5 miles. Now, if I turn advanced track off, I can drive it and no issues and the AWD shows on dash that torque going to front and rear when I accelerate. I've put several hundred miles on my Edge with advance track off and no light, but as soon as I drive with advance track turn on with in 6.5 miles it is only torquing to the front and code sets. Turn key off open door restart and turn advance off issue gone. Any help would be appreciated. Do yall think it could still be the ground issue? I've got over 143K miles now and up to now no issues with anything and oh by the way I have a tune in my Edge and I've even reflashed to stock tune and no difference. Thank you, Larry Bacon