Grab a bru, this is a long post but I hope you will benefit from my experience/ mistakes!!!
I had a similar issue "Check VSC" but with code P2757 - I think I have fixed it, taking 3x oil changes (9l of Toyota WS ATF @ £15 p/l), a new SLU solenoid (£250 from Lexus) and 2x shudder fix (£15 from eBay, friction modifier), 2x AT filters and gaskets - the gasket is not reusable and must be changed and you must use sealant to mate the sump with the AT unit. And about 6 hours in total of ramp time (3 hours each time @15ph) - first time a mechanic pal did me a solid.
In line with previous comments of dirty or blocked solenoids, the new solenoid was fitted with a filter.
I believe the issue was caused due to poor maintenance - the oil looked dark, like it was burnt - so I have to accept that I may have delayed the death of my gearbox and not fixed it completely but it seems to be pretty much as smooth as it was less the check VSC.
1st attempt - drained the AT changed the filter and ATF - the code and the check VSC came back, now with a shudder too, noticed when going up gentle inclines! And in the extreme cold, the car almost had zero power pulling away - after a couple of minutes it pulled away fine.
2nd attempt - drained the AT, changed the SLU solenoid and refilled - check VSC disappeared but the shudder remained and the problems with pulling away from a cold start in the extreme cold (1C or below) remained.
On attempts 1 and 2 - I followed some advice to get ATF temp upto 40C and then allow the expanded fluid to seep out of the overflow - when it stops, seal.
3rd attempt - drained and refilled with a new filter and also added 2x tubes of shudder fix, I added 3l of ATF and sealed the tranny without going through the overflow procedure - ALL PROBLEMS FIXED!!!
The ABSOLUTE key was measuring how much ATF came out on attempt one, which I failed to do but I know it was roughly 3l.
Other lessons which might help -
- a bracket secures the two exhaust pipes at the front end of the AT unit which obscures some of the sump screws - you might get away with removing one side and just pulling it down and out of your way - those nuts and bolts on the exhaust can get pretty corroded for obvious reasons, in the UK!
- use only the recommended fluid for your transmission - I've learned this from painful experience messing around with a ZF transmission on a Jag S-type in the past.
- YOU MUST measure what comes out of the transmission - allow it to cool before measuring volume, BEAWARE - when you remove the AT filter more fluid will come down!!!! Be ready to catch.
- These Units are not opened, and come as sealed Units, so open the fill cap before you drain or you'll be totally screwed if the fill is stuck!!!
- You can do this job on your drive BUT I would urge you to rent a ramp, it can get messy.
- spend £15-20 on a decent hand pump, you'll need to hand pump ATF back in to the Unit.
- watch this video first, it points out the key stages for this job!