The problem of the car engine is related with this engine P1809 Code and it is important to know the real cause of the car engine problem. Here, Detonation or spark knock can be a cause of the engine problem. Because these things buildup of too much pressure and heat in the engine’s combustion chamber. You should check or hear a metallic knocking or pinging noise. So, you will understand about the car engine problem. A minor amount of detonation frequently will not reason major damage and this can be ensured when it is tested properly by an expert automobile engineer.