VSC initialization speed - 2002 SR5

[bytemaster0]

I have a 2002 4Runner SR5 4WD, equipped with VSC (as were all models from 2001-2002 and on.) I purchased the vehicle used with 117,000 miles last April. Since I have had the vehicle, I've noticed a peculiar behavior from VSC, specifically related to when it will initialize. I've had lots of work done on the car (all steering components replaced, rack, intermediate, and upper steering shafts to alleviate play in the wheel), and some work to replace an axle seal, an O2 sensor, and a couple other minor things. Here's what happens:

Before I get to the problem, the manual clearly states that "VSC is active at speeds above 15 kph (9MPH)."

1. If I start the car, and then drive at speeds below 25 MPH (remember, manual says VSC should now be active), and I trigger an oversteer or understeer situation between 10-25MPH, VSC does *not* activate, or even try to intervene. The car will either go sideways or miss the turn. It seems that no matter how far I drive, unless I exceed 25-30MPH, VSC will not initialize and be ready to run.
2. If I restart the car, then drive above 30MPH, and attempt the *same* test between 10-25MPH, VSC works *flawlessly.*

So, it seems that no matter what, in order for VSC to initialize itself to be ready to work, I must drive above 25-30 MPH *first.*

I have called Toyota HQ (not that they'd really know much), who told me this is abnormal behavior. I then went to a dealer, and replicated the problem. The service technician agreed with me that this was not normal behavior for a vehicle. However, he had no clue what to do (the car isn't throwing any codes whatsoever), and that he'd have to call Toyota in California. Apparently, after doing so, the information that the service manager attempted to relay to me is that this was normal behavior.

I don't believe this for one minute; ABS initializes itself properly at 5MPH+. ATRAC goes live from the moment the key is turned, and the vehicle's steering position sensor has been zero-point calibrated several times now. The yaw-rate and lateral-rate accelerometers all should be working well without needing to go over 30MPH, and any problems with self-check should occur well before 30MPH.

I know that one should not drive dependent on such technologies, and I do my best not to. However, not being sure that the system is active (I shouldn't have to police myself to see whether I've driven 30+) is somewhat scary. I'd prefer to have it active from the moment I start driving.

Can anyone else replicate this problem? I can't seem to find anything like this anywhere, so feedback is much appreciated. So, any other 2001-2002 owners experience the same issue? Thanks for chiming in!

Edit: The zero-point calibration has been done at least twice recently, due to the steering component replacement.