16514 - Oxygen (Lambda) Sensor B1 S1 fault code

[pvcprinting]

OkOn going problem with the EMLWhen I check the fault codes, i get 16514 - Oxygen (Lambda) Sensor B1 S1: MalfunctionP0139 - 008 Implausable SignalI clear the code and the EML goes out and car runs great from cold. After I have stopped and re start the EBL light comes back onI thought as i go over quite a view speed bumps that it might have been the plug. Disconnected the plug and re seated it.Same thing happens over and over againChecked the resistance between pins 3 & 4 and got 3.5 OhmsWhat else can i check to diagnose the problem?Thanks in advance