Quote:
Originally Posted by Nomake Wan
I figured that, Trevor. However, what I didn't understand is why cruising around, it stays at half-engaged instead of going to fully-disengaged.
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Nomak,
Solenoid valve “B” is normally closed and energised to open. When at a duty ratio of 95% the valve is opened to drain and no lock up duty pressure is available. As a result the lock up control valve, through a pressure differential arrangement, causes lock up.
This set up is possibly the reverse of what you may have assumed, but the end result is as you will have expected. The pressure differential arrangement assists with smooth partial engagement when SV “B” is part open, say 50%.
You have advised, ---
”If the transmission is in "Normal" mode when you disengage the cruise control, it drops to 55%, but does not go down to 5%. So when driving around without Power Mode, the torque converter appears to be in a semi-locked state."
SV “B” is under direct control from the TCU and vehicle speed, engine speed and the selector signal are all involved in the control of lock up. Therefore a signal could be present which you have not taken into account and further observation may provide a clue. Unfortunately there is no evidence within the available data which otherwise explains your findings.