DTC P03B9-00: Cylinder 4 Pressure Too High: General Description

Cylinder compression pressure of the turbo engine is higher than non-turbo gasoline engine. Therefore pre-ignition in turbo engine brings damages of cylinder block and spark plug, piston. ECM monitors the signal of knock sensor to detect pre-ignition in each cylinder. ECM limits maximum torque by rich lamda control, reducing load, retarding ignition timing and reducing valve overlap when it detects pre-ignition.