Yes and Yes.
If I unplug it it makes a bunch of noise.
Its reading data Through it, I can see all the voltages on eaxh of the battery packs ( 1 through 20) and they all show 15.0 or 15.1.
are the batteries vin locked? I havent read of any need to reprogram after switching them. My mechanic read that it is a ground issue, and it could be in the
inverter. I was wondering if that would need reprogramming after changing? Ive got a full parts vehicle here, minus the transmission to take parts from.

 

Batteries are not VIN or vehicle locked. Yukon, Sierra, Silverado, Tahoe, Escalade are interchangeable.

 

what about the inverters? The unit under the hood?

 

No idea.

 

P1AE7 = "The drive motor generator battery control module has detected a loss of isolation between the high voltage positive or negative bus to chassis ground that is less than 200 k Ω."
You could have an internal short in the battery. The high voltage cables in the battery could be shorted to chassis ground.
"A single high voltage contactor relay stuck closed can set this DTC."

 

So this could be one of the two high voltage relays at either end inside the battery? I have 2 spare ones, any idea how I would test them?

 

With power off, check resistance between the two terminals of the relay. Should be open circuit or huge Ω. Best to test with a megger if you have one.

This code sounds highly similar to Toyota's P0AA6 - HV isolation fault.

This can occur in (in order of likelihood):
Battery (95%)
Transaxle (3%)
A/C compressor (<2%)
Inverter (<1%)
HV Wiring (<1%)

Disconnect battery computer. With voltmeter set to Auto or 200VDC, check for voltage between the main (+) terminal to battery case bottom and the (-) terminal to case bottom. If either measurement registers a voltage, the battery has leaked and is triggering the isolation fault.

 

Just to clarify, would this be the 2 main leads coming out of the battery? would I do this test with the safety plug in or out? (the big orange disconnect)

 

No. Those are isolated by the relays. Since you already have the cover off since you're testing relays, you simply tap the main (+) and (-) directly from the battery. Safety plug presence doesn't matter.

 

So this would be the main (+) or (-) ? I can't remember wh

ich it is as it's back in the truck now.