Engine fault diagnostics (VW Polo 4)

Gasoline engine: when the engine does not start, a systematic approach is needed to identify the fault. In general, for a gasoline engine to start, 2 main prerequisites must always be met: the fuel-air mixture must enter the cylinders and there must be a spark on the spark plug electrodes. Therefore, first of all, it is always necessary to check whether fuel is being supplied at all. How to act in this case is described in the sections "Power supply system" and "Engine management system". If a malfunction occurs in the engine management system, then the malfunction can only be determined using special measuring instruments.

For a diesel engine, check the preheating system and fuel supply system.