Bosch SMS 503 Dishwasher?

We have had our dishwasher from new and is now 16yrs old, which says allot for the build quality.

However, it has recently started stopping part way through the cycle, either between wash and rinse or rinse and dry. No set pattern. I think the problem lies with the programmer.

The machine itself is still in remarkable condition, apart from this current problem. But bearing in mind it's age would you say it is worth having it looked at and roughly what are the costs involved?

Thank you for any advice.