You’re totally right about this. I’d say there’s a very wide range of quality between various manufacturers’ FSMs. Toyota ones are great with diagnostic instructions and explicit parameters to match, whereas other brands I’ve leafed through have completely muddy pictures and poor instructions or no figures.
For third parties, I find Bentley manuals to be extremely good and thorough.
The car that I'm most interested in fixing something on at the moment is a Toyota, so that's great to hear about their manuals. If one finds a manual from the manufacturer itself is it safe to say that that's the true FSM versus something else they may have produced?
For third parties, I find Bentley manuals to be extremely good and thorough.