The car loan, being secured on the vehicle will not be in the IVA and you will continue to make payments as normal ( this will be part of your agreed allowances, as long as your creditors agree that the vehicle is acceptable). However, most lenders do have insolvency clauses allowing for repossesion in the event of insolvency ---- you will have to look through your terms & conditions from the lender for this.
Many firms, even with such a clause, do not concern themselves as long as the payments are continued and only your lender will be able to say which way they are likely to jump.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk