Purchased a 2002 C70 in August With 152000 MI. I do not know the vehicle's history but since I've had it there is visible white smoke coming from the exhaust be error codes were 236, 237, 455 and 335. I was very careful when I replace the turbo pressure valve at the airbox. The car drove very rough so I parked it. when I return to the car the next day the battery was dead. I have replace the ignition coils and the spark plugs along with other sensors and the car still will not start. I checked the vacuum connectors after turbo pressure valve they seem okay but the car still will not start. When I turn the ignition key I do not hear be fuel pump and it still will not start nor do I hear a tick tick tick please help?