Well worth it to try a “known good” SD card.
If the unit works for awhile “over the road” in automotive service
then your main suspicions should be effects from
vibration
heat
corrosion
Electrolytic capacitors of the past failed a lot because “knock off copies” had incorrect chemistry that copycat manufacturers failed to steal the secrets of.
Todays electrolytic capacitors are much improved but can still fail from high heat or high corrosion.
Do more goggle searches for service manuals, etc
because you need “pin out voltages”
to greatly help your troubleshooting.
Get the best magnifier you can borrow and very slowly compare solder connections one to another looking for flaws and color differences.
Pay extra attention to everything around the slot connector for the SD card.
If the read/writes to the SD card are generating lots of random errors
It is logical that the software would shut down the hardware once so many errors had occurred
Does anyone you know have the same camera, that still functions?
Reading all pins for voltage while the “known good” device operates.would give valuable clues about which component on the “bad” board has a problem.
It would be a hundred times better if you could observe both voltage and “trace” on pins with an oscilloscope.
Does anyone you know have a “thermal camera” ?
Looking at a board and seeing all the temperatures as varying colors would help spot the problem component.
You may not have a thermal camera but you do have the crude temperature sensing ability of a fingertip.
I realize asking about these specialized expensive tools is unlikely to be worth the money for an inexpensive camera,
but after the coming Chinese/USA nuclear war
and all the damage from EMP
survivors will badly need such tools,
if it is actually worth being a survivor.....
