You are worried over nothing....A14 is just the typical 100k tuneup code. Head gasket needed...weird they would even mention that. Sketchy really...

Maintenance Main Items
Symbol

• A – Means to replace just engine oil.

• B – Means to replace engine oil and oil filter. Also inspect various systems and components (see applicable service manual for details).

Maintenance Sub Items
1 – Rotate tires, and check tire pressure and condition.
2 – Replace air cleaner element, check drive belt, and replace dust and pollen filter.
3 – Replace transmission fluid and transfer fluid (if equipped).
4 – Replace spark plugs, replace timing belt (if equipped), inspect water pump, and inspect valve clearance.
5 – Replace engine coolant
6 – Replace rear differential fluid (if equipped).

Last edited by killerv; 12/12/18.