Gearbox ECU
NISSAN X-TRAIL (T30)

I have a 2002 x trail,
auto. Problem started when I was going up a slight incline, did the kick down
to drop a gear. It dropped down then went up a gear and down then up then
stalled. This happened a few times then engine management light came on, Took it
to a garage who cleared the fault then said it was the gearbox sensor. Drove it
away a few yards down the road it stalled again. when being driven it struggled
driving, when I eased off of the throttle it recovered itself but occasionally
stalled. Had it recovered to another garage who said the gearbox ECU is
corroded. new one is major surgery. Any idea if the ECU can be cleaned or what
may be done to resolve other than spending £2K for a new unit…. if it is that.