We use pronouns in place of nouns when we don’t want to repeat the same noun again and again.
“it” refers to “my car”
Subject pronouns come before verbs.
Object pronouns come after verbs or after prepositions.
Possessive adjectives cannot be used alone. They need a noun.
Possessive pronouns must be used alone. They cannot be used with a noun. They can be a subject or an object.