Q: Epc light on a 2009 audi a4 quattro centre brake light warning also wont start

Missing or malfunctioning lights will not prevent the car from starting. If the brake light switch is faulty that might prevent shifting out of Park once the car is running as the switch is part of the safety interlock to prevent unintended vehicle movement. To resolve your issue, the trouble codes should be downloaded with the expectation that they represent, or refer to, the underlying fault. With the codes, you can commence a diagnostic. With no codes, or if the codes refer to irrelevant components, check for fuel pressure, actual injector operation, and spark. If the engine is not even cranking, though, the starting circuit is instead diagnosed beginning with the engine immobilizer (i.e., be sure the alarm is off). In all probability, in your case the trouble codes will have enough information to resolve the issue. If you have any further questions we are always here to help you and of course you can request the check engine light diagnostic which will enable you to obtain a speedy resolution once the codes are downloaded, interpreted and followed up on.