Just got my Prius back from its HV ECU replacement. It turns out that the part number has not changed it is still 89981-47040. Did a search on the groups site on that number and found this post from last year around this time:
[Allen Massey groups post# 8529 http://groups.yahoo.com/group/toyota-prius/message/8529
Sun Mar 11, 2001
A few months back I discussed this problem under the
heading "Surging". I have spent a lot time working with my dealer
and last week we finally replaced the main computer (part number
89981-47040). This seems to have fixed the problem. It took my
dealer two months to get the computer in after placing a special
order. And when it did come in he did not know how to install it
correctly. It turn out that you need to take a copies of your keys
when they replace the computer because they must reprogram the new
computer to accept your keys (this takes 45 minutes per key)
What he told me was if the version number of the software in the
computer is 5 or less then you may have the surging problem.
So my recommendation is for everyone that is having this problem to
force your dealer to replace the computer as soon as possible. This
is something you really do not want to pay for yourself since the
computer cost is about $2,000.]
My question to the group is where is the ECU located and has anybody seen the version number on theirs?
BTW the work order says: PULLED CODE P3115(SMR) INFO #1 (224)
(NEEDS RE-MODIFIED HV ECU)
PERFORMED TSB EG009-01.REPLACEMENT OF HV ECU.
PREVIOUS PART# 89981-47040. REPLACEMENT PART# (SAME)T