If you're scouring the skill menu in The Sims 2: Bustin’ Out on PlayStation 2 looking for a "Mechanic" skill, you won't find it. The console version uses a different skill system than its PC counterpart, and the closest equivalent is the Mechanical skill.
Skills in Bustin’ Out max out at level 10, not 5. There is no dedicated "Mechanic" career branch. The Slacker career does feature a "Mechanic" chance card, but it's entirely random. If you want to fix things fast, pour points into Mechanical—it's the only skill that matters for repairs.