[jnads]

So to me they are going to have to crack open every one of our transmissions once they design a new wiring harness.

This is bad, really bad.

Before you jump to conclusions, we'd have to see exactly where this part is.

The transmission is actually bolted to the side of the engine and the power inverter module (PIM) is at the top, you can see it from the engine bay, with the orange wires.

If the faulty connection is in the PIM, then it's less intrusive than you think.

 

[jnads]

Hey everyone, factory tech here whose personally diagnosed these a decent amount of times this year.

To keep it simple the A drive motor has three resolvers: sin, cos, and excitement. In all cases I’ve seen, the cos resolver is shorting to the transmission case and causing a short to ground condition. It is either intermittent, and will cause a random stall, or shorts in such a way that you can instantly see it on a DMM and the vehicle won’t start and the code will be active

For those wondering, the part mentioned is here:

YOUTUBE

As an engineer I'd guess the part that fails is that in-line SIP wire connector. It looks like the part is meant to be protected against failure by that robust bracketing system, but I'd guess that plastic cracks due to the lateral stress on the connector (or maybe people are swinging it around by the wire harness at the factory).


The resolver is the electric motor equivalent to a crankshaft position sensor. Essentially the vehicle is shutting down because the sensor goes faulty and the vehicle doesn't know the position of the motors / how fast they are spinning, which could lead to fighting between the motors (burn out the PIM) or fighting with the engine.

I'm guessing the software update allows everything to keep working for a limited amount of time if such an error occurs since there's nothing physically keeping from the motors working, just if the drivetrain gets too out of sync it can lead to damage.