P0730 - autobox fault code

[mkaminski100]

Again and again...more problems.
Today I was checking my car and found P0730 fault code in autobox.
I don't know if it's a gear ratio again and if yes, maybe this is my low MPG problem?
Is it possible that the gearbox is slipping so some of the power is lost, or a TC is dying and it's slipping or is harder to turn?

My OpelScanner shows (on P and idle):
Coolant temperature in automatic gearbox tab - -50C (minus 50)
Oil temp - 43
Desired Torque control: 91%
Pressure regulator Solenoid Valve: 773 mA
Calculated pressure: 4,6 Bar]
Band Apply Solenoid: 51%

(on D and idle):
Coolant temperature in automatic gearbox tab - -54C (minus 50)
Oil temp: 44
Desired Torque control: 91%
Pressure regulator Solenoid Valve: 889 mA
Calculated pressure: 3,7 Bar
Band Apply Solenoid: 0%


Can anybody help me to get my car fixed? I can pay to fix my car, but want to be sure what is the reason.
Thank you in advance

[Marks DTM Calib]

That is an indication of convertor slip and normaly results in limp mode being activiated and the fault warning appearing on the display.

As a starter, I would check the fluid level in the autobox (see the maintenance guides)

As far as the coolant temp is concerned, I would ignore the reading as there is no coolant in the gearbox or coolant temp sensor so I suspect its an eronious reading.

[mkaminski100]

If you wake me up in the middle of the night and ask how to top up I will tell you... I will check the level today to be sure but I know that I had a revs problem with normal oil level.
Sassanach dismantled my autobox few weeks ago and found nothing suspicious. Everything like new, no sign of wear or damage. Still thought I am having problem with this box. There are two ways of making this problem. First, when accelerating slowly up to 20MPH, I found that on some stage, speed is still but revs are going down around 50-100 (I think that TC is doing it's job), but when I keep the same speed, suddenly revs are going up and the car is like on N mode. I never tried to put more throttle, just changed to N and to D again. Once i just let the throttle and after few second felt a clonk and car was on gear again. Once I just hit the throttle and revs went up to 4000 and it started to get a grip at this revs. I never tried to drive like this.
Second situation is when going up on the hill, it will try to reduce the gear. Same thing - accelerating gently, autobox will just loose a gear and I have to change it to N and D again or wait for a clonk.
There is no limp mode, just this problem.

Previously I changed my autobox ECU with the same model but with 2.5 engine firmware. It was driving even better, but when accelerating on the motorway it was going to limp mode again (wrong ECU, and wrong engine cut-off point). I knew that there is no problem with the gearbox itself, just a software issue, I was doing 70MPH and found that revs were on the same level but MPG went dramatically down. That's why I am just thinking if there is a control issue or a TC problem in my gearbox and it's slipping all the time/ the box is making high resistance so the engine is loosing a lot of power to supply the box.
I just don't know how to check that.