What causes no spark or injector pulse on a 2004 Volvo S80?

No spark or injector pulse on a 2004 Volvo S80 can be caused by several issues, including a faulty crankshaft position sensor or camshaft position sensor, which are essential for engine timing. Additionally, problems with the ignition control module, engine control unit (ECU), or wiring/connectors can disrupt signals needed for spark and injector activation. A weak battery or poor ground connections may also contribute to these symptoms. Diagnosing the issue typically requires checking sensor outputs and the integrity of the ignition and fuel injection systems.