Honda Odyssey Exclamation/VSA warning with transmission issue?

Our 2005 Odyssey has recently been having issues when making a sharp turn (U-turn, 90 degree turns, etc.). The yellow exclamation point and the VSA warning light turn on and the van can't shift gears and as I bring it to a stop it shakes and shudders. When I turn the van off and restart it a few seconds later, the problem is fixed (until the next sharp turn), leading me to believe it may be a computer issue and not a transmission issue. It seems not to happen when taking a slower, wider turn when possible. Anyone had this happen to them? Any suggestions on who best to take it to - dealer, Sears, or independent mechanic?

The first thing you'll need to do is make sure the engine oil level is full, low oil level will make the VSA light to turn on and will make the car feel like loosing power; also checking and make sure the charging system is good. That's mean the battery, its cables/ terminal, the alternator need to be tested. Is any other light lit up besides the VSA? CEL? TCS? ABS?

The second thing is check for code(s) in the system so the diagnose will go on the right direction. The cause(s) could be anything and it won't be a guessing game because everything is costly in part(s)

Depends on how many codes. It could be the Yaw rate sensor, the Steering angle sensor, the grounds, the connections at the VSA/ABS/TCS controller, connections/ power and ground at the PCM, same with the VSA controller (Vehicle Stability Assist), WSS (Wheel Speed Sensors) the gap between the WSS and the tone rings. Etc

Don't forget basics, I have in the past found out almost any misfire, crank sensor glitch, etc can cause the VSA or TCS light (Intermittently) and abrupt hiccup.

So check for the codes first. Code(s) cause by the engine operation will sometimes affect and trigger the VSA/TCS light. The light is a one trip code, the code for the engine is two trips code and sometimes the check engine light won't lit up.

Edit: You think that what I have told you is weird? I've found in the past on Honda/Acura has intermittent lit up the TCS light caused by a defected brake light switch. Try to step on the brake to put it in gear and see if the light turn off. Send an E mail if you need more information. HTH