In Californa, a lender has four years to file a lawsuit against you to collect a debt based on a written contract. Generally, the four year period begins when you default on the second mortgage. Your default probably began just after the date of the first missed payment on the second mortgage. However, depending on the circumstances of your case, this could vary.
If this written contract is governed by CA law, the 4 year statute would start to run from the date of your breach, which is usually the date you made your last payment to the lender.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.