If your knock sensor is working properly and it detects detonation then the ECU lowers the boost (if your boost solenoid is still connected), retards the ignition and puts more fuel in to protect the engine. This is temporary until the detonation has stopped and this does not show a fault code. If there is a fault in either the sensor or the wiring then the ECU will show a code 34 and take the above measures on a permanent basis until the fault is fixed. When it is in this safe mode the car feels a lot slower than usual.oz_R_Jr said:what dose your car do when u know the knock sensor has packed it in????