proper trained mechanics outside of Pakistan do not do component level repair on parts like sensors but they get trained and tested to "identify the actual problem"
I had a person contact me through PW to help on his mercedes benz gearbox, his complain was that it was stuck in 2nd gear, The mechanics had failed to pinpoint the problem and were suggesting to replace the gearbox control unit, the gearbox itself, the wiring to it and the shifter.
Its a pretty tall order - the gearbox alone costs about Rs 200,000/- in junk. The control unit is about Rs 100,000/- for it
I wrote a systematic approach and asked him to get his mechanic to test it, it was also inspected via his skype phone, The problem was the shifter was bad, how did we see that? We tested the CAN BUS signal to the shifter, the gearbox controller was transmitting a request for position but the shifter was silent - nothing coming back, Replacement shifter resolved the problem, Total cost for shifter was less than Rs 40,000/- in used part, he sent me over USD 200/- as a gift without me asking for it. Car was back on road. The sad part was that his mechanic had the correct scan tool but could not understand what it was showing. Its menus were a little strange compared to generic ones.
Best part was that the job was over in 1 hour testing, shifter replacement takes about 1 hour. The culprit was a nice cup of tea emptied in the shifter.
I wish that other car owners follow such practice and not believe in the "bypass - jugaar - chaaloo kaam" procedure, I take pride in what I do - this is a hobby of mine - but even in professional career my work always has standard to it.
Not trying to toot my own horn but just giving you an example.