The chip is still in circuit and I found a buried forum post saying that the board may be drawing power from the programmer and preventing the chip from getting the power it needs. I'll skip the frustration of the past few weeks and innumerable failures to read from the chip and jump to this afternoon, when I finally was able to see the chip's contents. I've picked up a spare Toyota ECU and a little TL866 programmer.
I'm trying to virginize the ECU rather than pay the stealership over $1000 to do it. Long story short, I bought a car with an immobilizer and no master keys.
