NHTSA Complaint #11431167 — 2005 TOYOTA SIENNA

Stability light comes on, decelerates independently, vehicle shakes and steering is somewhat compromised. This has happened rounding curves between 40-50 MPH. Has happened twice on straight road, 8/24 and 8/25/2021, traveling at 70MPH, vehicle decelerated 2-5 miles independently. I put signal on and did smooth lane change to the right to get out of fast lane, and stability light came on, vehicle shook and steering was somewhat compromised. Neither local mechanic or dealership can retrieve any codes with diagnostic equipment. Dealership told me today the light has to stay on for them to retrieve code. This has happened irregularly over the last 6-8 months but always on curves. It has occurred 4 times in 6 days last week, twice on curves, 8/23 & 8/28/2021, and the 2 lane changes above. I am concerned with the increased frequency. There is a great deal of information on the web at https://www.siennachat.com/threads/traction-control-malfunctioning.44474/ so this is not an unknown issue.