"he took his car in for service",here "service" means "routine inspection and maintenance of a vehicle",then what does "took in" here mean?

Nothing really remarkable or difficult about this. "in" refers to the garage where the inspection is to be done. The owner "takes" the car because he is the agent for moving the car from one place to another. "Take" can mean either the action of "bringing to" or the action of "receiving" (sometimes without the owner's permission). In general, it implies moving something from one place to another and the kind of transaction is usually indicated by a preposition. The difference between "take" and "bring" is purely relative: 'taking' is usually the action of removing something from somewhere; 'bringing' is the action of carrying something to a place. Depending on how I feel about the action (and who I am speaking to at the time), I might use either to describe the same action: To a friend, who isn't involved with the servicing of my car: "I am taking my car [in] for a service tomorrow." To the garage responsible for the work: "May I bring my car in for a service tomorrow?" to which they might answer, "Yes, we can take it in first thing." or "Yes, can you bring it at 8am?" Some interesting usages to ponder on: "If it rains, I must take in the washing" (where 'the washing' refers to clothes which have been washed and are hung outside to dry). (As a request:) "Oh, it's raining! Please bring in the washing!" "In order to earn a little extra, she takes in washing." (She is a laundress and earns a little extra money by washing other people's clothes. Notice that there is no definite article.) "Take" can also be used figuratively to mean 'understand' as in "I take your point." and "I take it that you don't want to accept the position." To "take a leaf out of someone else's book" means to use someone else's idea or to follow their example. In England, we have restaurants which serve hot food packaged to be taken home and not eaten on the premises. We call them "Takeaways". In America they are called "Take outs". Charities sometimes hold events called "Bring and buy" sales. You are invited to bring things for them to sell and to buy things that others have brought. I might search through my unwanted things and put them ready to take to a 'Bring & Buy' sale. Perhaps the items were, after all, unsuitable - the person running the stall might say: "Oh, we can't take these!" (such events can't usually accept electrical items), so I might have to 'take' OR 'bring' them home again.