Originally Posted by wstar

EDIT: Scratch that idea, there's no easy way to fake it with a relay. Most of it is trivially fake-able since it's just "apply voltage to energize" and 2x redundant inverted feedback status switches that inform BCM + IPDM E/R whether the lock is in the commanded state, but then there's one critical bit that wouldn't work out: the BCM feedback on pin 111, which actually expects some timed pulses and state changes from some controller inside the lock unit in response to lock/unlock commands. So you'd need something a little more complex to fake it, like a cheap little microcontroller.

Even if you replaced the lock unit with a microcontroller-based fake: if you ever turned the steering wheel while the BCM thought it was locked, I wouldn't be surprised if it a threw a code because the steering angle changed when it shouldn't be possible.