I'm not sure how it is on Q45's, but I have replaced the contacts and plunger in my 1999 Toyota Avalon. Took a weekend mechanic like me about 2 days (between a full time job) to figure everything out, but with some telephone help from my mechanic, I totally surprised myself... I didn't have to totally replace it like the local Auto parts store jerks were saying, and fixed it for about $50 in internal parts. As opposed to $125 for a brand new starter, or $225 to have the contacts replaced by a mechanic. I wouldn't hesitate to take it apart on a Q if I could get to it.