would the dash emission light cause the car to stop, unable to restart at all? on 2003 Volvo XC70

car lost power, cut out and wouldn't restart. engine turning over, but not firing.Mechanic changed cambelt sensor, with no effect. emission light been on for 6 weeks, could this be a cause?

Asked by for the 2003 Volvo XC70
what is the eng codes he had?