Hello all, could anybody tell me whether the bosch motronic 4.3 managment system uses a floating earth for the lambda sensor or a chassis earth? The earth reference voltage at the moment is 700 mv approx which is causing the lambda signal to switch between 700mv to 1.5v.I have tried driving the car with the sensor earth connected to battery ground & it doesn't seem to effect the drivability or the trims on live data,even the injector duration hardly changes when the earth is connected/disconnected at idle, but that is whilst observing live data which is probably slow at updating on this system. If anybody knows what the earth should be , it would be appreciated. Regards, Andrew