Thermador GGSCV365 XLO Burners don't work

Hi

I have a Thermador GGSCV365 cooktop. First, one of the XLO burners stopped working. Then the other stopped working. When I turn on either XLO burner, there is no spark and there is no gas. The other 3 burners work fine - when turned on, they get gas, get a spark and light. Any idea of what part(s) need to be replaced?

Thanks