The issue (and code) will likely only be logged on faster roads with lots of airflow. At this point the tempreature will start to drop, in town or slow speed stuff, a dodgy thermostat won't show up.
Yes you will need a good toolset really. Nothing amazing needed. E10, E18/E16 and TX45 or TX55 for the torque converter bolts, plus the guibo bolts.
Won't be a fun job on the floor.
Your codes is indicative of a thermostat failure more likely than the sensor IMO.
If your oil temperature also fails to get HOT (80+) and stay there then its likely going to need a thermostat, its a sizeable job and engine out on the GT due to a supporting beam directly in front of the housing...
Abs light caused by the sensor will only illuminate when your moving.
If the light is on all the time after start, likely to be the relay(s) on the pump or fuse to the pump.
If it comes on only after moving then likely to be a sensor.
This:
U040283 Historic: Implausible data received from Control Unit Transmission. The Checksum has an incorrect value.
Is a giveaway that its a control unti fault.
Checksum is something an embedded computer does to ensure its brain isnt faulty.
It has a stored value for a caulcation (EG...
I can regularly hit 65+ on a run with no electric contribution.
My daily commute averages 3 mi/pkwh which is quite good for a big heavy car but relatively poor compared to dedicated EVs