This chick wanted a nice car and.... Well read more...

[jimmy57]

530d is the code that says there is a fault in the TCM that requires the emissions malfunction indicator lamp, MIL or what most call check engine light, to be lit. The code(s) in the TCM Is the damning one. There are pressure switches on a cover on valve body and the TCM can diagnose solenoid issues by comaprison of the solenoid control and the expected on or off signal from switch.
You probably have a solenoid that is sticking and not changing position for the 3rd shift. Is the fluid nasty or gray?

[chipmunkbug]

I changed the fluid and filter and yes, the fluid looked terrible and there was a massive buildup of metal on the magnet.

[chipmunkbug]

The solenoid will change to third, idk about 4th, when it is cold. What does that mean?

[dcarlson12]

What does 'idk' mean? Or is it a typo?

[chipmunkbug]

sorry. I am typing on my phone. Idk means I don't know.

[jimmy57]

Given the metal on pan magnet your trans is likely misbehaving due to a failure that lets fluid leak out of seals. When bushings supporting rotating clutch drums fail the piston ring type seals will not seal the bore to the journal where the fluid feed holes are located. No way to know without a teardown but the prognosis is not good that solenoids or any external fix will do any good.